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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: Double-A on October 27, 2015, 01:16:29 am

Title: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on October 27, 2015, 01:16:29 am
I am having a problem with my instrument lights and DRLs not working in my 1986 Chevy K20 Scottsdale. The original headlight switch connector is gone (previous owner thought he was an electrician) but the headlights work. And when I put the wires that don't work on the headlight post the DRLs work but the instrument lights still don't. I checked the fuse it's OK. But the fuse terminals are dead.

Hopefully you guys can help me,
Aaron
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Captkaos on October 27, 2015, 01:19:44 am
Day Time Running lights?  These trucks didn't have those...
What actually works?  The headlight and marker lights, no lights?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on October 27, 2015, 03:33:32 am
The orange lights in the grille are the drls I've heard. Different names I guess. But at the moment only the headlights work. If I switch wires around on the headlight switch I can get the orange lights to work but that sacrifices the headlights. The brake lights and turn signals all work as do the high beams.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Captkaos on October 27, 2015, 03:37:57 am
Those are parking lights.  Daytime running lights are white.
There is 2 positions on a factory headlamp switch.  1 click out is parking, all the way is all lights. 
Do the headlights work in both locations, or does it have nothing like the factory switch in it?

For all power both park and headlights will burn.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on October 27, 2015, 03:43:07 am
It has a factory style switch. It was replaced by a previous owner. One click out does nothing.. No lights at all. All the way out just the headlights come on, no parking lights.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Captkaos on October 27, 2015, 03:26:52 pm
If 1 click out does not turn on the parking lamps you have it wired incorrectly.  That should turn on the parking lights (all lights except the headlights)
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on October 27, 2015, 04:48:06 pm
A dead tail lamp fuse supply socket indicates loss of power into the fuse box.  Find the two-post junction block mounted to the firewall above the back of the engine.  Give the red wires (fusible links) connected to the junction block a tug to see if any of them stretch or pull apart.  Factory power routes directly from the firewall junction block, through a fusible link and bulkhead connector into the back of the fuse box.  The running lamps and instrument lamps are on the same circuit.

Use the 1986 Wiring Manual (http://www.73-87chevytrucks.com/techinfo/7387CKMans//Wiring/ST_352_86_1986_Chevrolet_GMC_Light_Truc_Wiring_Manual_CK_10_30_Only.pdf#page=10) for reference.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on October 29, 2015, 01:57:20 am
I have it wired up like the wiring diagram shows.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on October 29, 2015, 08:33:18 am
Have you checked the fusible links and verified power through the firewall bulkhead connector?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on October 30, 2015, 04:18:56 am
I haven't. I have the headlight switch wired like the diagram I have shows to. I can't really look at it any this weekend though.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on October 30, 2015, 04:20:06 am
Also if my tail lights work wouldn't that mean the tail light fuse is OK?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on October 30, 2015, 11:14:02 am
Quote from: Double-A on October 30, 2015, 04:20:06 am
Also if my tail lights work wouldn't that mean the tail light fuse is OK?

In your original post you stated that, "the fuse terminals are dead."  Were you referring to the tail lamps fuse or the instrument lamps fuse or both?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 03, 2015, 03:01:36 pm
I was referring to the instrument panel light fuse
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 03, 2015, 05:00:44 pm
Regarding the instrument lamps, make sure the headlamp switch knob is rotated completely CCW, just short of turning on the dome lamp. 

For the tail lamps to function, but not the front running lamps, implies a faulty connection through the firewall bulkhead plug or open in the brown wire that leads to the forward lamps.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 04, 2015, 01:02:19 pm
Ok. I'll have to go look at the firewall connector. The switch is rotated as you said when I test it. I'm pretty sure the brown wire is OK but I'll check that as well.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 04, 2015, 03:40:16 pm
Sooner than later, you should plan on replacing that missing headlamp switch connector.  They are available from  AutoZone (http://www.autozone.com/electrical-and-lighting/headlight-switch-connector/duralast-headlight-switch-connector/chevrolet/k20-3-4-ton-p-u-4wd/1986/8-cylinders-l-5-7l-4bl-ohv/739228_0_0/),  NAPA (http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Headlight-Switch-Connector/_/R-ECHEC20_0334571670),  O'Reillys (http://www.oreillyauto.com/site/c/detail/BWD0/PT181/03574.oap?year=1986&make=Chevrolet&model=K20%2BPickup%2B4WD&vi=5002287&ck=Search_03574_5002287_3505&pt=03574&ppt=C0189),  Classic Parts (http://www.classicparts.com/1967-87-Headlamp-Switch-Connector/productinfo/55-502/#),  etc.


Pick up a 20-amp, auto-reset circuit breaker (image) and attach a couple of 12" 16-gauge leads with insulated alligator clips.  This will make a handy jumper for testing.  Do you have a test light?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 04, 2015, 11:26:23 pm
Ok. The connector I'm talking about has a red and a white wire. I think it's still in the truck is just not attached. And if I remember correctly I tested it's wires for voltage and they were dead (not 100% sure I'll check that as well) and I don't have a test light but I have a multimeter
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 07, 2015, 08:26:27 pm
Quote from: Double-A on November 04, 2015, 11:26:23 pm
Ok. The connector I'm talking about has a red and a white wire....

What connector are you talking about?  Post a pic.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 10, 2015, 05:10:43 am
I'll post a picture of it tomorrow if i can. But it has a white and red wire in it. And it appears that it once connected towards the front of the switch because the connector is setup to be a perfect fit there.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 10, 2015, 09:52:58 am
In the meantime, the OE harness connects to the headlamp switch through a single connector, imaged below.

To review:
Red is battery power into the switch for the headlamps, only.
Yellow is switched power out to the headlamp dimmer switch.

Orange is 20-amp fused battery power into the headlamp switch for the running lamps and instrument lamps, only (the redundant orange jumps power to the under dash mounted courtesy lamp).
Brown is power out to the park, tail, and side marker lamps.
Green is rheostat controlled power out to the 4-amp instrument lamps fuse.  At the instrument lamps fuse the wire color changes to gray and continues onto the instrument cluster lights.

White is the headlamp switch controlled ground circuit for the cab dome lamp.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 11, 2015, 04:19:57 am
It looked similar to that but only with 2 connections it wasnt a big connector like that either just enough for 2 connections. Now there is no connector at all and just spade connectors for each wire. If that picture is how its supposed to be then there are a few connection issues. Ill wire the switch like the picture and see if that works.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 11, 2015, 11:48:22 am
Remember, way back at the beginning...

Quote from: Captkaos on October 27, 2015, 03:26:52 pm
If 1 click out does not turn on the parking lamps you have it wired incorrectly.  That should turn on the parking lights (all lights except the headlights)

Pick up the proper connector and match the wire colors of the pigtail to the factory harness.  You should be good to go....
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 11, 2015, 10:44:19 pm
So where would the white wire connect to? I dont see it in the picture you posted or in the picture of the connector at the parts store. I see the other wires in the correct areas just not the white one.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 11, 2015, 11:31:56 pm
Referring to the image, above, the white wire from the cab dome lamp inserts into the open cavity directly below the red wire.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 13, 2015, 01:13:28 am
Ok thanks. Tomorrow I will see if that works and if it does i will go buy the connector.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 14, 2015, 04:40:08 am
Well my switch doesnt look like it would work with the picture you put up. My picture is how the wiring diagram I found showed to wire it.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 14, 2015, 01:03:06 pm
You're basing your switch wiring on bad information!  If those are factory wires in your image and not random colors a PO has spliced in, then only some of the connections are correct.

Download the factory GM 1986 Wiring Manual (http://www.73-87chevytrucks.com/techinfo/7387CKMans//Wiring/ST_352_86_1986_Chevrolet_GMC_Light_Truc_Wiring_Manual_CK_10_30_Only.pdf) to your hard drive and go to page 11.  Use the schematic in conjunction with my prior post...

Quote from: bd on November 10, 2015, 09:52:58 am
Red is [constant] battery power into the switch for the headlamps, only.
Yellow is switched power out to the headlamp dimmer switch.

Orange is 20-amp-fused, [constant] battery power into the headlamp switch for the running lamps and instrument lamps (the redundant orange jumps power to the under dash mounted courtesy lamp).
Brown is power out to the park, tail, and side marker lamps.
Green is rheostat controlled power out to the 4-amp instrument lamps fuse.  At the instrument lamps fuse the wire color changes to gray and continues onto the instrument cluster lights.

White is the headlamp switch controlled ground circuit for the cab dome lamp.

Notice there are two constant B+ feeds into the headlamp switch:  the 3 mm2 (12-gauge) red (Ckt 2) is for the headlamps, only - the 0.8 mm2 (18-gauge) orange (Ckt 40) is for the instrument, park, tail and marker lights.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 14, 2015, 08:06:23 pm
The only non factory wire is the blue wire which is the headlight wire.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 14, 2015, 10:35:50 pm
Is the blue wire constant hot?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 15, 2015, 04:54:14 pm
Yes I was remembering what it did. The blue wire I believe was a quick fix to get the headlights to work and it is hooked straight to the battery.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 15, 2015, 07:34:55 pm
Then, does the "white" wire in the image feed the headlamp dimmer switch?

In the top left corner of your image, appears to be a "yellow" wire.  Where does it go?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 16, 2015, 05:55:01 pm
I don't know exactly what the white wire does. If it was the feed how do I check? As for the yellow I will have to check what it does.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 16, 2015, 08:22:16 pm
Let's try a different approach....

(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=31989.0;attach=30916;image)

The "green" and "brown" wires appear to be connected to the switch correctly.

DO each of the following exactly as stated, and ANSWER each question in turn...

First, you need to determine whether the "blue" wire is fused.  With both the ignition switch and headlamp switch turned OFF, connect your voltmeter between the "blue" wire and ground - the meter should indicate battery voltage.  Does it?

Now, remove the "tail lamp" fuse and recheck the "blue" wire using the voltmeter.  Does the meter still indicate battery voltage?

Next, reinstall the "tail lamp" fuse.  With the ignition and headlamp switches still turned OFF and both doors completely closed, connect your voltmeter between the "white" wire and ground.  What does the voltmeter indicate?

Finally, with the ignition and headlamp switches still OFF, connect the voltmeter between the "yellow" wire and ground.  What does the voltmeter indicate?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 16, 2015, 09:04:55 pm
The wire that is connected to the top right corner in the picture is not white. I'll be able to tell you what color it is tomorrow. And I'll answer the questions tommorow as well
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 18, 2015, 03:16:07 am
The wire in the top right of the picture is yellow. I couldnt tell in the picture. I wasnt able to go out and to the tests you posted today because it was storming here and my truck lives outside D: Tomorrow hopefully it will be nice enough to do the tests.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 18, 2015, 06:20:30 am
Also. The wires in the top left are the orange pair. Sorry for the confusion.. It's a pretty tight space to get a good picture. 

The wire colors on the switch in my picture are
Top left: orange
Top right: yellow
Left of yellow : brown
Directly below yellow: green
Bottom right: blue


The white and red wires are disconnected at the moment.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 18, 2015, 09:24:28 am
The wire colors are in the correct positions on the switch.

So, "blue" is substituting for "red."  Ignore "white" for the time being.

Are the "orange" pair constant 12 volts?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 18, 2015, 05:32:51 pm
Correct, it appears that the blue wire is acting as the red wire. The blue wire has voltage, and I found the red and white wires, the red wire has no voltage. And the orange pair also have no voltage.

These tests were all done with the ignition off and the driver door open.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 18, 2015, 06:18:56 pm
You are making progress!   ;)

The orange wires should measure 12-volts at all times.  They are powered off of the 20-amp "T/L CTSY" fuse.  Recheck that fuse.  If the fuse is good, remove it and check for corrosion on the fuse terminals.  If there is no corrosion, then there is an open in the orange wire between the fuse box and the headlamp switch.

If you determine the orange wire is open, make up a fused jumper as previously described, and temporarily jump power to the headlamp switch terminal occupied by the orange wires.  The tail and instrument lamps should now operate with the switch.  Trace the orange wires back to the fuse box to find the open circuit.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 18, 2015, 07:38:36 pm
Alright I will check all of that stuff tomorrow. I am fairly certain that the fuse you are talking about is fine and has no corrosion but it doesnt hurt to double check.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 18, 2015, 08:33:38 pm
And, be sure to verify that there is 12 volts at the 'T/L CTSY' fuse.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 19, 2015, 05:21:30 pm
Alright. I rechecked the blue and orange wires again with the ignition off, the switch pushed all the way in to off, and the driver door open. Blue still has voltage and orange is still cold. The Tail/CTSY fuse is fine but the terminals are dead. I didn't look for an open in the wires yet (its a mess... so much electrical tape) but I did jump the blue to the orange and the parking lights worked, but I couldnt tell if the instrument lights turned on. They however did not operate with the switch, (Im guessing because the terminal had voltage?) as soon as I put the jumper on the blue wire and connected it to the orange terminal the lights turned on... with the switch off.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 19, 2015, 05:36:43 pm
You earlier stated that the red wire is dead too.  Open the hood.  Look for a black-plastic, two-post junction block, about 2 inches square, mounted to the firewall above the back of the engine.  There are several wires connected to it.  Grab each wire, in turn, and give it a firm tug.  Do any of the wires stretch or did any pull apart?  Do any appear overheated or burned?

Do the same thing at the starter solenoid.  There are two 12-gauge red wires that connect to the 3/8" battery cable stud on the starter solenoid.  The two red wires attach to the solenoid through 6" long fusible links.  Give the red wires a tug to see if either stretches or pulls apart.  While you are there, make sure the battery cable connection to the solenoid is tight.  If the cable is loose, disconnect the battery before tightening the retaining nut so as not to short the cable to ground.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 22, 2015, 06:48:04 pm
Ok, sorry for the late reply, it got kinda busy here. I think i found the black plastic junction box ( http://imgur.com/5Np1SlX ). There was a loose wire because its terminal wasn't crimped well but nothing stretched or came apart. The blue wire has an inline fuse but doesn't connect to anything.

The starter looks new to me.. ( http://imgur.com/Yd8NA8W ) Anyways, it was very difficult to see the wires but I tugged on them and none stretched or fell apart. I think the fusible link is the wire that has a silver colored shield, but I'm not sure. I couldn't see any of the wires you talked about in your last post that are on the starter.

I can't really get any better pictures than the ones I posted links to because the starter is in a really tight place, I cant see it from the top of then engine and it looks like all the wires are on the top of the starter.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 22, 2015, 07:36:18 pm
Quote from: Double-A on November 22, 2015, 06:48:04 pm
i found the black plastic junction box ( http://imgur.com/5Np1SlX ). There was a loose wire because its terminal wasn't crimped well but nothing stretched or came apart.

The green oxidation at the junction block indicates overheating caused by connection problems.  The red wire with the yellow terminal maybe the feed into the headlamp switch.  If it is, the PO removed the factory fusible link (NOT GOOD)!  Important: does that red wire run into the firewall bulkhead connector below the windshield wiper motor?

Quote from: Double-A on November 22, 2015, 06:48:04 pm
The starter looks new to me.. ( http://imgur.com/Yd8NA8W ) Anyways, it was very difficult to see the wires but I tugged on them and none stretched or fell apart. I think the fusible link is the wire that has a silver colored shield, but I'm not sure. I couldn't see any of the wires you talked about in your last post that are on the starter.

The purple wire with the wire tie looks like the solenoid "crank" circuit from the ignition switch.  Use a mirror, being careful not to touch any wires.  Is it connected to a small #10 machine stud on the solenoid?  How many wires attach to the battery cable stud at the solenoid?

The adjacent reddish wire looks like a fusible link.  You need to route both of those wires (purple and red) away from the exhaust manifold, otherwise the exhaust heat will burn the insulation and ignite a fire.  The 'silver' jacketed wire at the starter is probably a short jumper that connects the solenoid to the cranking motor. 
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 22, 2015, 08:28:42 pm
The red wire with the yellow terminal doesn't connect to a bulkhead connector, it goes straight through the firewall (there's a hole with a bunch of other wires running through it). So do I need to replace the little junction box or find a fusible link?

As for the starter area, I will have to go get a mirror tomorrow or something. And I saw a heat shield on the exhaust manifold by the starter so hopefully that's a good thing.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 23, 2015, 01:30:47 am
Before I can help you with what to repair, we need to clearly establish what you presently have.  It seems the supply wiring has been altered from the factory configuration.  We need to determine to what extent, so you can safely restore power to the fuse box and headlamp switch.

I want to begin by determining where the various wires connected to the firewall junction block run - where they go.  (If the blue wire at the junction block doesn't connect to anything, it can be eliminated).  I also want to verify how battery power is routed into the cab and to what extent the factory circuit protection has been circumvented.  You may need to fabricate and install some fusible links.  The process isn't difficult, but follows an exact formula.  I will inform you when you get to that point.  The firewall junction block should clean up with some careful scrubbing with a compact stainless steel wire brush and some WD40. 

But first, post a pic of the bulkhead connector that clearly shows the wire colors entering the engine compartment side of the connector and the relative positions of the wires with respect to the connector cavities.  Are there two 12-gauge red wires entering the bulkhead connector?  Use your voltmeter to determine whether both red wires are constant 12 volts.  Assuming the 6.2 diesel, the opposite ends of the red wires should connect to the firewall junction block through a fusible link, and the alternator 2-cavity regulator connector, respectively.  Do they?

The 2-cavity regulator connector also should have a 6" fusible link that jumps between the terminal shared by the 12-gauge red wire and the 1/4" output stud of the alternator.  This fusible link is the circuit protection for the headlamp switch.  Give it a tug to see if it stretches or separates or if the terminals appear burned. 

Determine where the remaining wires attached to the junction block go.  One of the 12-gauge red wires should run down to the starter and share the 3/8" solenoid post with the battery cable.  Does your truck have a trailer brake?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 23, 2015, 01:57:17 am
The only question I can answer tonight is the trailer brake. It does have a trailer brake, it was installed by a PO, however it seems to work. I can't test that though cause I don't have a trailer.

I will answer the rest of the questions tomorrow or later in the week.

I'd like to thank you for all your help so far too.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 25, 2015, 07:54:00 pm
Ok. I took a picture of the firewall connector that I think you spoke of ( http://imgur.com/a/0323V ). I took a few pictures to try and get as many details as possible. Most of the wire's shielding is faded and I cant really tell what color they are (sorry). The connector also looks awful, like its been melted, and I don't know why...

It does look like that connector has 2 12 gauge wires but I am not sure if one goes to the alternator. The wires connecting to the alternator are a larger (12 gauge I think) yellow wire, and 2 smaller red and white wires that are in a plastic connector. I am not sure if they have fusible links.

 One of the wires on the firewall connector looks like it could go down to the starter. I didn't have time to see where the wires on the firewall connector went.

I hope this info helps.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 25, 2015, 08:48:34 pm
Thus far, I've assumed and based my discussion on your 1986 K20 with 6.2L diesel.  Am I correct in this assumption?

FYI - The black-brown "GOOP" that fills the bulkhead connector cavities is a thick, anti-oxidant/sealant used to protect the electrical connections from moisture and other contamination.  It can create the appearance of being burned.

Looking at the image, below, the upper leftmost 12-gauge red wire (circled) should connect to the alternator regulator through the two-cavity (3-wire) plug.  The 12-gauge red wire in the center of the image (circled) should run to the firewall junction block.  Do your best to verify the wire routing.  Post a pic of the wire connections to the alternator.

With your voltmeter clipped to a good clean ground, back-probe the two red wires (circled) in the bulkhead connector using your voltmeter.  Both should measure constant battery voltage with the ignition OFF.  Do they?

The firewall junction block should receive battery power through a single 12-gauge red wire connected to the starter solenoid battery cable stud.

I suspect that the red wire with yellow terminal attached to the firewall junction block that runs into the cab through the grommet in the firewall, connects to the trailer brake control.  Please take a moment to verify this if you can see the wire inside the cab.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 26, 2015, 02:42:12 am
You are correct about assuming my truck is a 1986 K20 with 6.2 Diesel.
How can I probe the connections you want me to probe at the firewall connector? I don't see a way  of disconnecting it..
The alternator on my truck doesn't have a 2 cavity 3 wire plug. It has a 2 cavity 2 wire plug (they are white and red wires) and a lug with a 12 gauge yellow wire.

I'll do the rest of the tests tomorrow and see about that wire on the junction block being the trailer brake control.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 26, 2015, 11:49:42 am
Quote from: Double-A on November 26, 2015, 02:42:12 am
How can I probe the connections you want me to probe at the firewall connector? I don't see a way  of disconnecting it..

Shove the positive probe of the meter through the 'goop' into the cavity occupied by the wire you are probing until it touches the terminal (roughly 3/8" give or take).

Quote from: Double-A on November 26, 2015, 02:42:12 am
The alternator on my truck doesn't have a 2 cavity 3 wire plug. It has a 2 cavity 2 wire plug (they are white and red wires) and a lug with a 12 gauge yellow wire.

Post a pic of the wire connections to the back of the alternator.  To what does the opposite end of the 12-ga 'yellow' wire connect?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 27, 2015, 09:24:30 pm
Ok. The wire you circled in my picture and labeled as "Alternator" has no voltage. The other wire you circled does though.
The wire you suspected as the trailer brake control is indeed one of its wires.

The yellow wire on the alternator goes to the glow plug controller ( http://imgur.com/DO9Zyyu its the wire on the top lug that's yellow )

Here is the back of the alternator ( http://imgur.com/Pe7Lv0R sorry its hard to see but there are a bunch of things in the way.) The stud has the yellow wire I described that connects to the glow plug controller.

I didn't test the junction block cables to find the power for it. I will do that tomorrow if its still important after this info.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 27, 2015, 10:00:25 pm
You're making good progress and have narrowed it down, significantly.  Now, you need to focus on the 12-ga red wire at the bulkhead connector, labeled "TO ALTERNATOR" in the previous image, AND on all of the wires connecting to the alternator.  I'm guessing that someone replaced the alternator and regulator pigtail, and in the process neglected to reconnect the 12-ga red wire that runs to the bulkhead connector. 

Look closely behind and around the alternator for the "abandoned" red wire from the bulkhead connector.  It may be bare or it could have been taped up in the loom out of sight.  Hopefully, it wasn't removed. 

Move some of the things that are shrouding the back of the alternator and post a few more pics of the alternator wiring, especially the wires attached to the output post and where/how the red & white regulator pigtail is wired in.  Remain diligent.  You are almost there.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 28, 2015, 01:01:51 am
You are correct about the alternator being replaced. A PO replaced it. But all these wiring problems were done before the PO who replaced the alternator.
I will go take those pictures, search for the "To Alternator" wire, and find out more about the red/white pair.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 29, 2015, 06:31:45 pm
Ok.. I took some more pictures ( http://imgur.com/a/xKiNi Picture 1 is the alternator, picture 2 is showing what the yellow wire connecting to the alternator lug is.)
The red wire that connects to the 2 cavity 2 wire (red/white) is the 12 gauge wire I think.
I believe the wire that connects to the white wire is brown but it could be black.

 Again sorry its hard to see some of the stuff.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 29, 2015, 07:37:39 pm
Quote from: bd on November 04, 2015, 03:40:16 pm
Pick up a 20-amp, auto-reset circuit breaker...

     (http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=31989.0;attach=30812)

          ...and attach a couple of 12" 16-gauge leads with insulated alligator clips.  This will make a handy jumper for testing.

Use the described jumper to temporarily connect between the alternator output post and the "red wire" running to the regulator.  Do your running lights work with the headlamp switch, now?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 29, 2015, 10:02:36 pm
The output post is the one with the yellow wire correct?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 29, 2015, 11:08:48 pm
The output post protrudes out of the back of the alternator from a red plastic insulator.  I can barely make it out in your photo, but it looks like the yellow wire is attached to it.  Is there also a heavy gauge red wire connected to that post?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 29, 2015, 11:55:56 pm
The only wire attached to that lug is the yellow one. It's the red wire that is labeled "to alternator" in the other picture is spliced into the red wire that's next to the white wire.

Here is a picture with labels of what I mean ( http://imgur.com/oLM0kr2 )
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on November 30, 2015, 01:17:29 am
The charging system and glow plug wiring has been significantly altered from the factory configuration.  Bear with me.

With the engine off, what is the voltage at the alternator output post?

Does the yellow wire that runs between the alternator output post and the glow plug controller connect to one of the controller studs or the four-wire harness connector? 

Which of the two glow plug controller studs always measures battery voltage?

Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on November 30, 2015, 10:53:38 pm
Ok. I didn't do the test where you said to jump the output post and the red wire. I just did the ones in the last post of yours.

So the voltage at the output post with the engine off and ignition off is the full 12 volts. I should mention that there are 2 wires connected to the output post. There is the yellow wire, and a thicker (maybe 12-10 gauge) black wire that goes to a ground.

The yellow wire goes to a stud on the glow plug controller.

 http://imgur.com/a/6vbrz - Picture one- In green it clarifies which wire has the volts)
- Picture 2 is my glow plug controller. The yellow wire circled in blue is the wire on the alternator stud, and the orange circled post is the one with constant voltage.
 The other post doesn't have voltage and I didn't test the wires in the connector.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 01, 2015, 04:04:29 pm
Take another look.  The alternator output post cannot be grounded if it measures 12 volts!  Are you sure that "thicker black" wire sharing the post with the yellow doesn't connect to battery positive?  Disconnect the yellow wire from the glow plug controller stud - does the yellow still measure battery voltage?

Jump 12 volts to the regulator plug "red wire" then check for power on the 12-gauge red at the bulkhead connector.

Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 01, 2015, 06:50:08 pm
I am 98% posotive that black wire connects to the output post. I cant actually SEE it but I can feel that it goes and connects there...
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 01, 2015, 07:00:23 pm
Well I just went and rechecked. I didn't see in the dark last night that the black wire that is on the outpost connects to the positive battery terminal.

I didn't do the jump test yet, I'll try to do that tomorrow.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 02, 2015, 08:18:55 pm
Should I still do the test where I jump the 12 volts to the red wire?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 02, 2015, 09:39:41 pm
Quote from: Double-A on December 02, 2015, 08:18:55 pm
Should I still do the test where I jump the 12 volts to the red wire?

It's the quickest way to your solution.  When you jump power to the "red" wire, see if the running lights begin work with the headlamp switch.

BTW - Not to over stress the point, but when supplying power to an unknown circuit, it is risky to use an unfused source.  Hence, the recommendation to fabricate a test jumper "protected" by a circuit breaker or fuse.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 02, 2015, 11:16:39 pm
Alright. I'll probably have to do it this weekend cause I don't have any 20amp fuses laying around.

If it does supply power to that wire what would be the next step?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 02, 2015, 11:27:15 pm
Quote from: Double-A on December 02, 2015, 11:16:39 pm
If it does supply power to that wire what would be the next step?

Based on e/g we've discussed, there are several issues you will need to correct.  But, first, verify that power will actually reach the headlamp switch and the running lamps work when 12 volts is jumped as previously described.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 03, 2015, 01:34:51 am
Ok. One last question before I jump the wires... To test the headlamp switch should I keep how it's setup (blue wire as power) or should I wire it with the red and white wires? (They are currently disconnected and have no power... I guess my thought is if I jump the wires then maybe the headlamps red and white pair will have pretty again)
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 03, 2015, 09:31:03 am
Initially, just jump power to see what happens.  The more changes you make between checkpoints, the easier to become confused if something doesn't work as expected.  I'll provide a list of items to correct at the proper time and assist you through the process.  It shouldn't be horribly difficult with a few proper tools, just time consuming and methodical.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 03, 2015, 04:50:06 pm
Ok. I will have to go get an auto resetting circuit breaker from the parts store this weekend then. You posted that a 20 amp one would be fine or would lower amps be better?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 03, 2015, 06:04:28 pm
For general use a 20-amp breaker is very versatile and will work fine.  I wouldn't go any less than 15 amps.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 06, 2015, 07:26:24 pm
OK. Sorry for the late response. I jumped the output on the alternator with the red wire labeled "To Alternator", this gave that wire voltage like we thought it would. However the lights don't operate with the switch that way, instead the parking lights (the orange ones) and clearance lights turned on with the switch off and ignition off. The headlights still operated with the switch.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 06, 2015, 08:11:52 pm
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=31989.0;attach=30916;image)

Is the headlamp switch still wired as imaged?

The orange wires on the headlamp switch are supposed to be constant 12 volts.  They should become hot when the red regulator wire is jumped to B+.... 

Does the 12-ga red wire behind the dash for the headlight switch also become hot with the test jumper installed?  Do the dash lights illuminate with the dimmer rotated CCW when the jumper is installed?

So, the park lights and clearance lights illuminate as soon as you jump power at the alternator.  Do the 'park' and 'clearance lights' include the tail lamps?  If you unplug the brown wire from the headlamp switch, do the park and clearance lights continue to illuminate? 

So I can track with you, what exactly are you referring to as 'clearance lights?'  Does the cab have roof lights?  Or, are you referring to the side marker lamps?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 06, 2015, 09:03:33 pm
I'll have to do the tests tomorrow.
The parking lights I'm not sure if that includes the taillights I didn't think to check. But it includes the front orange lights in the grille and the side marker lights.

The clearance lights are 5 orange lights on the roof.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 07, 2015, 05:50:37 pm
OK. The parking and clearance lights include the orange lights on the roof, orange side lights, orange lights in the grille, and the taillights.

The headlight switch is still wired as pictured.

The orange pair are hot with the jumper installed.

The 12GA red wire behind the dash for the headlight switch is hot with the jumper installed. The dash lights still don't work at all (they did before I got it apparently).
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 07, 2015, 06:15:40 pm
Quote from: Double-A on December 06, 2015, 07:26:24 pm
I jumped the output on the alternator with the red wire ... the parking lights and clearance lights turned on with the [headlamp] switch off and ignition off....

Is this still true?

With the jumper installed, if you unplug the brown wire from the headlamp switch, do the running lights (park, tail, side marker & roof lights) continue to illuminate?

With the jumper installed and the headlamp switch turned on and rotated CCW, do you measure 12 volts on either side of the 5-amp "INST LPS" fuse?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 07, 2015, 06:31:14 pm
That quote is still true. The lights turn off when the brown wire is disconnected.
I will have to check the fuse terminals you speak of.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 07, 2015, 07:08:11 pm
OK. With the headlamp switch off and ignition off, and the jumper installed there was voltage at the 5 amp "INSTR LPS" fuse. With the switch on and rotated counterclockwise it still had voltage, the actual instrument cluster lights still don't come on. However I noticed that the Heater/AC selector switch light was on (I believe it would have come on when the switch was rotated counter clockwise without the switch itself being on)
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 07, 2015, 07:21:46 pm
With the jumper connected, does the INST LPS fuse lose power if you unplug the green wire from the headlamp switch?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 07, 2015, 08:27:51 pm
Yes it does.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 07, 2015, 10:44:28 pm
Following is a summary of the corrections I recommend.  I'll be happy to answer questions and assist you as you wish.  Perform all repairs with the ground cables disconnected from the batteries:
I think the foregoing list should address most of the issues you mentioned, although other issues may materialize as you progress.  Once the above is completed, you should evaluate the glow plug wiring as well.  It appears that the PO removed the factory fusible links protecting the glow plug circuit - a perfect setup for burning the vehicle to the ground.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 08, 2015, 02:34:13 am
I'm sure many questions will come up. I was unaware that the glow plug wiring has been so altered... they function like they should, but I should add that a PO added a push button to turn them on manually...

I am also not sure if there even is a instrument cluster ground, I believe the PO also replaced the instrument cluster and the instrument panel since they don't quite fit right.

I am not sure of what yellow splice you are talking about in number 6 too.

There is a possibility this truck will be sold though, it some other issues that I am not sure if its worth keeping over.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 08, 2015, 11:05:08 am
Quote from: Double-A on December 08, 2015, 02:34:13 am
I am not sure of what yellow splice you are talking about in number 6

Look at the attached image.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 08, 2015, 04:29:57 pm
Ahh ok. How am I going to get power to the headlight switch though? That red wire is the one I was jumping....

Maybe I need clarification on #6. Just want to be sure I am doing it right so I'm not like the PO.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 08, 2015, 04:52:41 pm
You will sever the red wires on the right, circled in yellow (previous image), and then rejoin them together with the new fusible link from the output post of the alternator. 

The three wires need to be connected at the new splice.  The splice joining the white and brown wires circled in blue should be replaced with an 18-GA splice (or 16-GA splice if the 18-GA is a little too small). 

Before assembly, the wire strands need to be shiny clean for solder to flow and properly adhere.  Don't forget to slip the heat shrink tubing over the wires before you crimp them together.  And then slip the tubing up the wire well away from the splice before soldering so it doesn't shrink prematurely.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 08, 2015, 05:42:34 pm
So just redo the splice on the brown wire (with a new fusible link), and the same for the red, but make another fusible link to go from the red regulator wire to the output post? Maybe I need a picture, I understand what I need to do but I guess I need to visualize it..
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 08, 2015, 06:33:49 pm
Commonly used automotive wire gauges are 18, 16, 14, 12, 10, 8, 6, and 4.  With respect to wire gauge, the greater the number the smaller the wire size.  Hence, 18-gauge wire is much smaller than 10-gauge wire; 4-gauge and larger wire is typically used for battery cables.

"Yellow" butt splices are for joining 12- to 10-gauge wires.
"Blue" butt splices are for joining 16- to 14-gauge wires.
"Red" butt splices are for joining 20- to 18-gauge wires.

The PO used 12/10-GA splices on everything regardless of actual wire size.  Replace the splice connecting the white and brown wires (blue circle) with the appropriate size (probably 18-GA).  That is, just cut the old splice out and then resplice the white to the brown.  You're simply downsizing the physical size of the splice to correctly match the wire sizes.  I directed you to do this, because mismatching terminal size to wire size can result in poor conductivity, especially as the connection ages.  The yellow butt splice is way too big for the white/brown pair.

The "red" regulator wire is the voltage sensing lead for the regulator.  It needs to be connected to battery (B+) so the regulator can do its job and control alternator output.  For now, the only new fusible link at the alternator is going to connect the two existing red wires to the output post (B+).  So, the two existing red wires will still be electrically connected; but now you will add a new fusible link that connects them to the alternator output post too.  In the process of connecting the three wires together, you will replace the existing splice (yellow circle).

Does this make more sense?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 08, 2015, 09:17:17 pm
Could you possibly show in the picture too? The instructions help a lot but I feel if I were to see what you mean I would understand much better. I dont really understand what Im doing with the red wire... I think I understand the white wire cause I am just supposed to redo the splice right?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 08, 2015, 10:37:39 pm
Continue to use both existing red wires, just "add" the fusible link as shown along with a new splice that is firmly crimped, soldered and insulated with adhesive lined, polyolefin heat shrink (available from Harbor Freight (http://www.harborfreight.com/42-piece-marine-heat-shrink-tubing-67598.html), Del City (http://www.delcity.net/store/Dual-Wall-Tubing/p_327) and many other sources).
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 08, 2015, 11:57:41 pm
OK, thanks, thats what I thought you meant.. I just wanted to make sure before doing it.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 09, 2015, 02:50:04 am
How long should the fusible link be that connects the alternator output with the regulator splice?

Also is the headlight switch wired correctly? What kind of headlight switch will I need, I notice there are some that say without post 7 or some that say they are 8 post..
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 09, 2015, 12:24:12 pm
Quote from: Double-A on December 09, 2015, 02:50:04 am
How long should the fusible link be that connects the alternator output with the regulator splice?

Also is the headlight switch wired correctly? What kind of headlight switch will I need, I notice there are some that say without post 7 or some that say they are 8 post..

Let's review...

(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=31989.0;attach=31178)

Use the embeded link in the following quote for specifics on making a fusible link...

Quote from: bd on December 07, 2015, 10:44:28 pm
...Cut the 16-gauge "red" wire coming out of the regulator plug at the alternator where it splices to the 12-gauge "red" wire that runs to the bulkhead connector.  Discard the yellow splice.  Make up a 16-gauge fusible link with a 1/4" ring terminal at one end (refer to How to make a Fusible Link (http://forum.73-87chevytrucks.com/smforum/index.php?topic=11972.0) in our Technical Pages).  Crimp the opposite end of the fusible link together with the "red" lead coming from the regulator plug such that both wires share the same end of the bare 12-gauge splice.  Slip heat shrink over the wire pair well past the splice and securely crimp the opposite end of the splice onto the 12-gauge red wire running to the bulkhead connector.  Solder the splice then heat shrink it....

Quote from: bd on December 08, 2015, 04:52:41 pm
... Don't forget to slip the heat shrink tubing over the wires before you crimp them together.  And then slip the tubing up the wire well away from the splice before soldering so it doesn't shrink prematurely.

Quote from: bd on December 08, 2015, 10:37:39 pm
Continue to use both existing red wires, just "add" the fusible link as shown along with a new splice that is firmly crimped, soldered and insulated with adhesive lined, polyolefin heat shrink (available from Harbor Freight (http://www.harborfreight.com/42-piece-marine-heat-shrink-tubing-67598.html), Del City (http://www.delcity.net/store/Dual-Wall-Tubing/p_327) and many other sources).

(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=31989.0;attach=30916;image)

Quote from: bd on November 18, 2015, 09:24:28 am
The wire colors are in the correct positions on the switch.

Relax and take a few minutes to reread the entire thread to help orientate yourself and bring all of the information into perspective.

As far as the switch is concerned, purchase a service replacement by parts catalog application.  The 7-post switch is fairly standard.  Splice the original harness to the new pigtail by matching wire colors.  The "white" dome lamp ground connects to the offset terminal at the right front corner of the switch, next to the ceramic frame.  It will need a factory style terminal to properly lock into the connector.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 09, 2015, 08:39:12 pm
Oh wow.. I didnt see half of the green letters in the picture from the previous post. This weekend I will be able to start on the list and will come back here with more questions if need be.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 15, 2015, 04:42:22 pm
Ok. sorry it took so long to get an update, this weekend was super busy.

In your list of things to do you wanted another picture of the junction block and its wires. Here's the picture of it http://imgur.com/v7LtmCX

One of the wires (circled in red) has a strange terminal that connects to both sides of the junction block. I'm not sure if that's right.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 15, 2015, 06:41:57 pm
The wire circled in red is factory - the metal link just ties the two studs together.  The three yellow arrows point to factory installed wires.  The blue arrow points at what looks like the power lead running into the trailer brake control (that new terminal end looks good  :) ).  Do any of the factory wires have what appears to be a splice roughly 6" - 7" away from their connection to the junction block?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 15, 2015, 07:28:01 pm
Thanks, I actually redid that terminal right before you posted that list.

And none of the wires have splices... they just run straight into the block.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 15, 2015, 08:58:30 pm
(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=31989.0;attach=31396)

I am guessing that wire #1 comes from the battery cable stud on the starter solenoid, wire #2 goes over to the firewall bulkhead connector, and wire #3 runs to the blower relay.  If this is correct, you can reassemble the junction block after applying a liberal coat of antioxidant to the studs, terminals and nuts.  Incidentally, wire #2 is a fusible link.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 15, 2015, 09:11:47 pm
Would it be ok to replace this junction block with something thats the same? I lost a nut when I was removing the wires and the 2 sides are different sizes...
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 15, 2015, 09:17:02 pm
You can, but the nuts are just standard machine sizes - I would guess 1/4" x 20 for the larger stud and #10 x 24 for the smaller. 
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 15, 2015, 09:21:16 pm
ok thanks
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 22, 2015, 01:37:16 am
Sorry there haven't been any updates, I haven't been able to do any work on it recently.. Been too busy with other things.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on December 22, 2015, 09:31:35 am
We've all been there many times.  Enjoy your family and Christmas!
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on December 22, 2015, 02:37:21 pm
Thanks, enjoy your Christmas and family as well.  :D
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 10, 2016, 05:09:59 pm
Hope everyone had a good Christmas and New Year, I will be starting back up on fixing my truck soon. Tomorrow I am going to get a new headlight switch and move on from there. I might have some questions but I'll see. Then we can move on to the glow plug wiring....
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on January 10, 2016, 09:43:19 pm
Pick up a connector pigtail, too.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 14, 2016, 03:37:55 pm
Well I got the switch and pigtail but it turns out my soldering iron broke. So it might be a few days before I can go and install the new stuff.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on January 14, 2016, 05:36:35 pm
The factory wires that were removed by the PO from the original connector [should] have the type of terminals imaged below.  Pick up a terminal removal tool (image), or make something similar, and remove the pigtail leads one-at-a-time from the new connector and insert the original wires matching color for color.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 15, 2016, 05:46:42 am
The terminals that are on there now don't have a tab to hold them in. It would be pointless to remove the pigtails connectors and put in the ones that are on it now..

I was going to use a linesman splice to connect the pigtail to the original wires.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 17, 2016, 11:45:50 pm
Ok well the headlight switch and its pigtail have been wired in using a linesman splice. I haven't gone to add the splice from the alternator output to the red wire to the dash because my brother who was a PO (not the one who altered everything) said that he removed a splice there because it was causing a parasitic drain. Maybe you can explain why it could/would cause that.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on January 18, 2016, 08:42:07 pm
How much of a parasitic drain in amperes?  Circuit 2 off of the alternator feeds the headlamps, instrument lamps, running lamps and horn.  On gas powered rigs it also feeds the ECM memory.  Did someone possibly tap Ckt 2 to power radio memory or ________?  Whether Ckt 2 picks up B+ from the back of the alternator or somewhere else is immaterial.  If there is a problem in the wiring or an appliance causing a parasitic draw of more than 50 - 60 ma it will eventually show up as a low battery unless the vehicle is run regularly to maintain battery charge.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 18, 2016, 08:58:14 pm
I'm not sure how much of a draw it has. I believe the yellow wire on it goes to the glow plug controller. But there is also a wire on it that goes to ground so maybe that's what causes the draw when a link is installed.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on January 18, 2016, 09:16:09 pm
What do you mean?  You already mapped out the yellow.  You said it connects to the G/P controller.  If there was a wire connecting B+ to ground, it would melt - quite spectacularly, I might add!

(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=31989.0;attach=31178)

Unplug the red and white wires from the regulator.  Connect a test light between B+ and the #2 regulator terminal.  Does the test light illuminate?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 18, 2016, 10:01:46 pm
Well there is definitely a wire going to ground from the post labeled B+ (its not melted but it must be wrong from the sound of it).

Tomorrow I will have to go see if there is voltage from the B+ to the area where the red and white wires connect. (I am assuming no but it doesn't hurt to check)
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 18, 2016, 10:17:49 pm
So if I am right about there being a ground on the B+ post is that wrong? Should I remove that ground? I again am assuming its bad by what you described and that there is a ground ( which is negative of course) and the post this ground is connected to is positive..
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on January 18, 2016, 11:01:24 pm
Remember these?

Quote from: Double-A on November 30, 2015, 10:53:38 pm
...I should mention that there are 2 wires connected to the output post. There is the yellow wire, and a thicker (maybe 12-10 gauge) black wire that goes to a ground....

Quote from: Double-A on December 01, 2015, 07:00:23 pm
Well I just went and rechecked. I didn't see in the dark last night that the black wire that is on the outpost connects to the positive battery terminal.

What changed since you posted these comments that a wire now goes to ground?



When you perform the quick test I mentioned, use an incandescent test light connected between B+ and the regulator #2 terminal with the regulator connector unplugged.  (The #2 terminal is the terminal that normally connects with the red wire).  In other words, I want you to connect the test light in series between battery positive and the regulator terminal.  Do not use a voltmeter.  In this case we are not interested in voltage, we are interested in current flow through the regulator sensing circuit.  The brightness of the test light will be an indicator of that current flow.

Was the alternator replaced before or after your brother removed the short jumper between the output post and the regulator circuit?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 18, 2016, 11:56:12 pm
Ah yes... I remember now. That wire is black so it confuses me..
I'll have to get a test light to do the test.

I believe my brother replaced the alternator and took the wire out in one sitting but I'll have to ask.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 19, 2016, 10:14:29 pm
Ok, so my brother did replace the alternator but I am not certain when he took the b+ to the red "to dash" wire out.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 22, 2016, 12:05:53 am
Sorry there haven't been any updates. I haven't been able to go do any of the fixes recently. I'm wondering do you still want me to put in the fusible link from the alternator B+ to the red "to dash" wire?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on January 22, 2016, 09:34:14 am
That red wire into the bulkhead connector has to be powered if you want the lights to work.  The red wire from the regulator connector has to be powered for the alternator to charge at the correct voltage.

Connect the red regulator wire directly to the output post of the alternator.

Connect the 12-ga red wire from the bulkhead connector to the alternator output post through a 16-ga fusible link.

And...

Quote from: bd on January 18, 2016, 11:01:24 pm
When you perform the quick test I mentioned, use an incandescent test light connected between B+ and the regulator #2 terminal with the regulator connector unplugged.  (The #2 terminal is the terminal that normally connects with the red wire).  In other words, I want you to connect the test light in series between battery positive and the regulator terminal.  Do not use a voltmeter.  In this case we are not interested in voltage, we are interested in current flow through the regulator sensing circuit.  The brightness of the test light will be an indicator of that current flow.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 22, 2016, 05:12:05 pm
Alright. You still mean like this picture right?

I still have to go get a test light..
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on January 22, 2016, 07:14:51 pm
You can mimic the image or you can install the link as follows...

Quote from: bd on January 22, 2016, 09:34:14 am
Connect the red regulator wire directly to the output post of the alternator.

Connect the 12-ga red wire from the bulkhead connector to the alternator output post through a 16-ga fusible link.

Both methods amount to the same thing.  The second approach might be a little easier.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 27, 2016, 06:28:25 pm
Well I havent been able to get a test light yet and I havent redone the wires by the alternator. But I went to start it the other day just to see if it could. Well it just turns over a few times before the batteries are flat.. Maybe this is just bad batteries but it started ok before I installed the new light switch with the correct wires instead of the blue wire straight to the battery.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on January 27, 2016, 08:10:53 pm
You started this thread three months ago.  How long has the truck been sitting unused?  Batteries can go dead due to a charge imbalance between the batteries, a parasitic draw, something inadvertently left on, or bad cells.  Cold temperatures don't help.  Over a really long period of non-use they can sulfate, diminishing capacity to the point of making them useless and unrecoverable.  Why don't you charge the batteries then disconnect both battery ground cables, making sure the batteries are disconnected from each other and the vehicle until you have the wiring repaired?  You can use a trickle charger to keep them charged and connect one back up temporarily if you need to perform a test.  Once the wiring is completed, the batteries can be evaluated.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 28, 2016, 03:34:45 am
The truck hasn't been unused the entire time.. It's been driven and started every so often just to make sure it still works. I never thought of disconnecting the batteries though (they are whenever I do a fix).
I still have to find a test light.. I'm not sure who will have any. I checked home depot today and they didn't have any.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on January 28, 2016, 08:35:32 am
Amazon (http://www.amazon.com/Wilmar-W2981-Performance-Circuit-Tester/dp/B000N321MO/ref=sr_1_8?s=automotive&ie=UTF8&qid=1453990315&sr=1-8&keywords=circuit+tester+automotive),  Harbor Freight (http://www.harborfreight.com/612v-circuit-tester-with-5-ft-lead-61652.html),  NAPA (http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Circuit-Tester-AC-DC-Current/_/R-BK_7001069_0361091527),  O'Reilly (http://www.oreillyauto.com/site/c/detail/PFM0/W2975C/N0221.oap?ck=Search_N0221_-1_3505&pt=N0221&ppt=C0371),  Summit Racing (http://www.summitracing.com/parts/pco-0690pt)  (red = better choices)

A test light is one of the best electrical troubleshooting tools you can own - inexpensive and nearly foolproof.  Procure an incandescent test light (replaceable filament type bulb) for 6- and 12-volt circuits.  DO NOT buy an LED or neon test light for general automotive electrical troubleshooting!
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 28, 2016, 08:39:12 am
Alright, I'll check O'Reilly's as there is one here in town.
Why won't a multimeter work though?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on January 28, 2016, 07:57:52 pm
Quote from: Double-A on January 28, 2016, 08:39:12 am
Why won't a multimeter work though?

A multimeter with appropriate current scales will work to check parasitic draw through the regulator with a caveat.  I prefer a test light, because it's reliable and there is decreased risk of blowing a meter fuse or damaging the meter if the circuit under test is shorted.  A test light connected directly across a 12-volt battery typically limits current flow to between 45 ma and 60 ma, depending on the bulb.  An ammeter imposes virtually zero restriction to current flow.  Additionally, some meter fuses are difficult to source and expensive.  What DC current scales does your multimeter have? 
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on January 28, 2016, 08:05:09 pm
My multimeter is a cheapy one.. Its says on it "Battery 9 and 1.5 volt"
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on February 01, 2016, 09:22:04 pm
Ok I got a test light. I am not sure if a radio was installed on circuit 2 like you were asking but I know an aftermarket one was installed. I removed it though and might try to find an oem one
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on February 01, 2016, 10:18:29 pm
Quote from: bd on January 22, 2016, 09:34:14 am
...  The red wire from the regulator connector has to be powered for the alternator to charge at the correct voltage.

Connect the red regulator wire directly to the output post of the alternator.

Connect the 12-ga red wire from the bulkhead connector to the alternator output post through a 16-ga fusible link.


I have attached a drawing to make sure I understand what you mean by this.
The photograph shows what you meant originally.

Tomorrow I will do your test with the test light and probably get the alternator wires ready.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on February 02, 2016, 12:27:17 am
Although either method for connecting the red headlamp switch feed to B+ will work, installing the fusible link according to your diagram offers a slight service advantage.

The subsequent test will indicate whether the regulator is internally shorted and causing a parasitic drain on the batteries.  With the battery connected and the two-wire regulator harness unplugged from the alternator, clip the test light to B+ and probe the alternator case (ground) to verify the test light is making a good connection; then probe the regulator terminals one at a time.  Probing the #1 regulator terminal should cause the test light to illuminate dimly.  Probing the #2 regulator terminal should not illuminate the test light at all.  Post what happens.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on February 02, 2016, 06:37:25 pm
Ok. I did your test (hopefully in the correct way) and redid the wires by the alternator.
I put one lead of my test light on the B+ post of the alternator and then put the probe on the alternator case. It lit up here.

I probed the terminal with the white wire (terminal 1 I think) and it lit dimly like you described.

I probed terminal 2 with the red wire and it did not light.

The test came out the same before and after I redid the wires.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on February 02, 2016, 07:14:00 pm
Good!  You just proved the regulator is not shorted and draining the batteries.  You should have power to the headlamp switch, now.  Correct?
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on February 02, 2016, 07:17:10 pm
I didnt test the switch but last time I did the jumper test (which is the same thing that fixing the wires would do) it had power. If I remember correctly though the switch turned on the headlights and the parking lights but the clearance lights turned on and then went out.. Im pretty sure they arent burnt out because they are new bulbs.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on February 02, 2016, 08:41:45 pm
The cab roof (clearance) lamps typically are powered off of a headlamp switch terminal that is adjacent to the tail/park lamp connection, or plug into a short brown pigtail off of the headlamp switch.  OE running lamp wiring is brown.  Try the running lamps and headlamps again.  If all the running lamps work except for the clearance lamps, there's an open in the brown wire running up to the clearance lamps or the lamps aren't grounding.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on February 05, 2016, 07:39:05 pm
Ok I got my batteries tested. They are fine it turns out. I started the truck and tried the lights. The headlights work (the front right top one doesn't anymore). But all of the parking lights including the clearance lights dont work.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on February 06, 2016, 08:16:39 am
Recheck the fuses.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on February 06, 2016, 07:16:25 pm
The tail/ctsy fuse was blown. I'll have to get a new fuse tomorrow (I don't have any 20amp ones on hand like it had) and I'll report back if it blows it again
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on February 06, 2016, 07:24:36 pm
Now I think you are getting down to the reason the PO hacked the wiring.  You probably have a wire in the running lamp circuit that is bare and touching ground.  A common place for this to occur is where the rear lamp harness passes over the rear axle on the inboard side of the left frame rail, close to the exhaust pipe.  Exhaust heat melts the wire insulation and the wires ground against the frame.  Inspect the rear lamp harness in that area and look for evidence of heat damage.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on February 06, 2016, 07:27:46 pm
Alright sounds like a good start
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on February 06, 2016, 07:32:37 pm
Quote from: bd on November 04, 2015, 03:40:16 pm
Sooner than later, you should plan on replacing that missing headlamp switch connector.  They are available from  AutoZone (http://www.autozone.com/electrical-and-lighting/headlight-switch-connector/duralast-headlight-switch-connector/chevrolet/k20-3-4-ton-p-u-4wd/1986/8-cylinders-l-5-7l-4bl-ohv/739228_0_0/),  NAPA (http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Headlight-Switch-Connector/_/R-ECHEC20_0334571670),  O'Reillys (http://www.oreillyauto.com/site/c/detail/BWD0/PT181/03574.oap?year=1986&make=Chevrolet&model=K20%2BPickup%2B4WD&vi=5002287&ck=Search_03574_5002287_3505&pt=03574&ppt=C0189),  Classic Parts (http://www.classicparts.com/1967-87-Headlamp-Switch-Connector/productinfo/55-502/#),  etc.

(http://forum.73-87chevytrucks.com/smforum/index.php?action=dlattach;topic=31989.0;attach=30812)

Pick up a 20-amp, auto-reset circuit breaker (image) and attach a couple of 12" 16-gauge leads with insulated alligator clips.  This will make a handy jumper for testing.  Do you have a test light?

Remember this post?

You could save yourself a lot of coin and streamline the troubleshooting process if you temporarily substitute a breaker for the fuse.  Add a 12-volt buzzer across the breaker and you will hear the buzzer every time the breaker pops.  Handy when you are crawling around under the vehicle or are in an awkward position.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on February 06, 2016, 07:40:34 pm
Ok that is an even better plan. I'll have to see if O'Reilly/HD has a buzzer.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on February 06, 2016, 07:59:25 pm
Look for a buzzer that is compact, lightweight and doesn't use very much current.  A plastic two-prong seatbelt warning buzzer is a good choice if you can find one that isn't expensive.  Best bet might be Radio Shack or similar electronics supply for a small, loud, 12-volt buzzer.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on February 06, 2016, 08:03:50 pm
Alright
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on February 07, 2016, 09:19:20 pm
Ok I have the new fuse and will start looking for the bad wire(s) tomorrow. I should mention my brother had to replace the passenger side tail light so maybe that is where an open would be.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on February 11, 2016, 04:41:20 am
Alright. I checked the areas you described. No wires were burnt, I am guessing because the exhaust pipes were hacked off to before the tires. I did get a picture of the harness where you would hook in trailer lights/electronics. It looks like there are a few splices and loose ends there. I didnt check the replaced taillight but I might do that tomorrow.

Here are pictures of the questionable area, its by the rear bumper close to the trailer hitch. (http://imgur.com/a/S3r47 I used this to maintain quality.)

The first photo shows 2 items circled in red. They look like they were once connected but aren't now? I am not 100% sure.

The second photo has the same things circled in red.
   The purple circle I think is bed sheetmetal to chassis ground (Needs cleaned badly)

   The yellow circle looks like it has been altered because of the electrical tape.

   And finally the black circle is a wire that looks like it was cut by something, but it goes to a license plate light.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on February 11, 2016, 06:00:37 pm
A)  The rubber connectors circled in red are for dual license plate lights.  It appears that one connects to the trailer plug.
B)  The frame connection circled in purple is a trailer ground.
C)  The taped bundle circled in yellow is after-factory splices into the OE rear lamp harness for the trailer lights.  I agree that they at least should be unwrapped and inspected.  In addition, inspect the trailer cord plug for muck and shorts.
D)  I don't see the "black circle" to which you refer, but the black arrow points to what I suppose is the trailer brake supply from the dash mounted controller.

Note that there are "Scotch Locks" clipped to a few of the wires above the frame rail.  It is prudent to suspect any wiring that incorporates Scotch Locks.  Scotch Locks are not intended for use in unprotected environments exposed to weather.  However, although intact Scotch Locks will not cause short circuits and therefore are not the immediate problem of blowing the fuse, they commonly result in intermittent and permanent open circuits. 

-----------------------------------------------------

You should isolate the running lamp wiring into zones to try and narrow the location of the short circuit causing the tail lamp fuse to blow.  You can rule out the instrument cluster wiring, since the 5-amp instrument lamps fuse is unaffected.  Isolate the roof clearance lamps, from the forward lamps, from the rear lamps, in stages.  You can do this without cutting wires by following the subsequent procedure.

Zone 1:  The brown wire feed to the roof clearance lamps should connect directly to the headlamp switch or plug into a short pigtail within about three inches of the switch.  Unplug the clearance lamp wire to see if the tail fuse stops blowing.  If the fuse stops blowing, the short is in the clearance lamp feed or roof lamps.

Zone 2:  If the problem persists, unplug the bulkhead connector from the engine side of the firewall and separate the rear lamp connector (the leftmost third of the bulkhead connector that is closest to the left fender and contains only four wires: yellow, light green, dark green and brown) from the main connector.  This step completely disconnects the rear lamps from power.  Reconnect the main bulkhead connector to the firewall socket and recheck the lights for blowing the tail lamp fuse.  If the fuse stops blowing, the short is somewhere in the rear lamp harness or rear lamps. 

Zone 3:  If the fuse continues to blow, unplug the bulkhead connector again and separate the left half (driver side) from the right half.  Reconnect the right half of the bulkhead connector to nthe firewall socket and recheck for blowing the tail lamp fuse.  If the fuse stops blowing, the short circuit is in the forward lamp wiring or lamps.

Zone 4:  If the problem persists, the short is in the running lamp wiring under the dash between the headlamp switch and bulkhead connector, or between the headlamp switch and instrument lamps fuse in the fuse block.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on February 12, 2016, 06:35:59 pm
This is just a little update.. I plugged in my little auto reset tester and the parking/clearance lights turned on with no trouble and didn't set off the breaker.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: bd on February 12, 2016, 07:01:20 pm
The short is intermittent, meaning it comes and goes.  It may be a bare wire that touches ground only occasionally as it shifts around.  Try nudging wires gently, especially in the areas where you recently worked (e.g., under the dash and at the back of the truck, etc).  It is possible that by moving the harness around during your recent inspections you temporarily "defused the bomb."  lol

Don't forget to take a look at the wires attached to the trailer socket.  Check inside the socket for mud and rust, too.
Title: Re: Instrument Lights and Daytime Running Lights Not Working
Post by: Double-A on February 13, 2016, 03:33:32 pm
Alright I'll look when it stops raining here.. No one likes working in the rain.