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73-87 Chevy _ GMC Trucks => Interior & Equipment => Topic started by: tpull123 on September 07, 2011, 09:13:52 am

Title: Trucks together....couple of electrical issues looking for advice on.
Post by: tpull123 on September 07, 2011, 09:13:52 am
So I finally thought I finished up my wiring and luckily most things are working considering this truck is 100% built piece by piece.    I have a couple of small electrical issues to sort out now and was hoping maybe someone with more experience on these trucks might be able to help track down the issues or identify if its a common issuse.:

1.  Gas gauge still not working, double checked all connections.....maybe its the sending unit??

2.  Dash blinker lights work fine with lights out, but when I turn the lights on, the right signal light shows green all the time (when lights are on) and doesn't blink with turn signal on??

3.  I don't have the parking brake, so I was using the ground connection hook up with my Line lock for a warning light.   Had key on power to line lock,  the ground from the line lock was wired into the wire ground for the dash light for parking brake and then both went to a  switch that the other lead was grounded.   The idea was to have the "Parking brake" light come on when the line lock was engaged.   I tested the circuit by grounding it out and the light would come on as it should.   Finished up the connections and heat shrinking, and now the parking break light stays on all the time, even after I disconnected the line lock stuff and the ground wire completely disconnected.   So somewhere its finding a ground, I chased all the wires and cant find anything that would cause it.....??

4.  My truck was an 86 and had what looks like to be an aux fan.   My question is since mine now has the Cummins motor I did away with much of the engine management system, I doubt any of those existing fan relays / controllers will work with my new system.   I am thinking of buying one of the after market fan controllers that have the probe in the radiator to control the electric fan.   Does that thinking sound logical?
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: Irish_Alley on September 07, 2011, 09:34:58 am
#1 most of us have that problem with fuel gauge. can be gauge or sending unit or connection. do a search on here you will see someone did a how to on testing the gauge with the dimmer switch.
#2 sounds like a bad ground/connection
#3 might be related to the ground problem in #2
#4 yes get the aftermarket stuff that way you know what you have and dont have to try and figure out what you need and how well it will work
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: Captkaos on September 07, 2011, 03:00:59 pm
ditto on the above,
For #2 check the bulbs in turn lamps
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: 1980c10 on September 07, 2011, 04:57:13 pm
For #2 the indicator stays lit to tell you that it's not working; i.e. a bad bulb but could be a loose wire etc.

#4. I have a "hayden" e fan wiring kit that works great. It includes an inline fuse, the probe and an adjustable thermostat.
I wired directly from the battery. The kit had everthing I needed from the battery to the fan. I picked it up at the local O'reillys.
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: beastie_3 on September 07, 2011, 06:07:43 pm
I have a adjustable thermostat kit for my electric fans too. I like it. I opted for the other kit that has the thread in sensor. I didnt like the idea of sticking the probe in the radiator. It could fall out too. I would also think it is less accurate.
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: 1980c10 on September 07, 2011, 08:56:48 pm
I would have prefered a thread in kit as well. My sensor is attached to the front of the radiator, accuracy doesn't matter but consistancy does and it seems like it does very well.
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: tpull123 on September 07, 2011, 10:09:39 pm
Thanks for the replies guys!!  I really wish I had even an complete truck to look at as a reference when assembling this thing, but you guys have helped a bunch!!

#1  I found the thread on how to check the fuel gauge, will do that when I get back from traveling!!

#2  Didn't know a bad bulb would do that.....good info!!

#3  Still think this one is going to be good ole fashion chase down, and probably hardest to fix.  Hopefully it isnt too bad to fix because it worked like twice and was awesome.   I used the existing fuel tank swtich (I only have one tank now), to kick on the line lock and the dash indicated it being on, all nicely hidden.   Amperage wise, the line lock doesn't pull that much so I can't beleive it would have melted any wires anywhere.

#4  I agree the thead in sensor is hands down the best, not sure which route I will go, but just wanted to check that the factory setup was of no use before I go hacking it off.

#5   In the mean time I found a couple of nice mods for the motor to up the power, should be hitting 350-375 hp and close to 800 ft-lb torque.   Can't wait to get her on the dyno.
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: Irish_Alley on September 07, 2011, 10:17:29 pm
never had a bad bulb turn the indicator on. not saying it cant happen but never been that lucky lol when ever i had a indicator on its due to a bad ground it will also affect other lights like maybe both turn signals will blink or all headlight will be on it can cause all sorts of problems. about the temp sensor on the rad. how do you think the clutch fan works. not saying not to do the thread in one but i dont think you need to.
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: Grim 82 on September 07, 2011, 10:33:04 pm
Blinkers:     These guys have you on the right track; for the $2 I would throw a blinker relay in it too and rule that out.
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: tpull123 on September 08, 2011, 01:07:12 am
I will double check all the grounds, the ones I have are all new and to clean metal, but i wont rule that out.   

As far as the radiator, it will be an electric and most likely the probe in the radiator since there was no room for the mechanical setup.   Still deciding if I want to get the one with the adjustable temp setting or the cheaper set tempature route.   I know the cheaper route is easily available at the local parts store, but feel the adjustabilty is probably worth the extra time and money......especially since it will be a probe and not a actual water temp.
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: 1980c10 on September 08, 2011, 10:09:22 pm
this is the one I used
http://www.oreillyauto.com/site/c/detail/HAD0/3653.oap (http://www.oreillyauto.com/site/c/detail/HAD0/3653.oap)
this is the fan btw
http://www.oreillyauto.com/site/c/detail/HAD2/3711.oap?ck=Search_N0646_-1_-1&pt=N0646&ppt=C0095
super easy kit
I didn't use their attaching method. I welded up some brackets for that. I also installed it between the grille and radiator(hidden).
the only issue I ran into; I increased the fuse size from 20 to 25 but the wiring in the kit is capable. The fan is rated at 17 amp but kicks about 21-22 amps at start then runs lower than 20 after that. My theory was that it could blow the fuse and I may not notice.
overall for under $150 I have a nice efan set up-no complaints at all and I am picky.

Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: tpull123 on September 09, 2011, 07:10:32 pm
@ 1980c10.....good stuff on the fan controller, it doesnt give a detailed description, but that looks to have the adjustable Pot swtich to control kick on....right?

I will prob pick up that kit, I already have a dual electric fan I picked up at the local pull a part for $20, and moves some serious air!!  Unfortunately, it will not fit as is, so I am going to split them apart and make a braket to hold them in.   I think I will start with one fan, and either I will add the second if needed.  If not needed...... I will have a replacement fan for the first one ;)
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: 1980c10 on September 09, 2011, 10:06:04 pm
@ 1980c10.....good stuff on the fan controller, it doesnt give a detailed description, but that looks to have the adjustable Pot swtich to control kick on....right?

I will prob pick up that kit, I already have a dual electric fan I picked up at the local pull a part for $20, and moves some serious air!!  Unfortunately, it will not fit as is, so I am going to split them apart and make a braket to hold them in.   I think I will start with one fan, and either I will add the second if needed.  If not needed...... I will have a replacement fan for the first one ;)

It does, I turn it with a screwdriver. Very simple. If you look up my project thread I posted the install within the pages of that.
http://forum.73-87chevytrucks.com/smforum/index.php?topic=12330.0 (http://forum.73-87chevytrucks.com/smforum/index.php?topic=12330.0)

Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: tpull123 on September 18, 2011, 10:20:28 am
Ok, finally back home and working on this thing again.   So for the Dash "Brake" light, I chased it through the electrical schematic and the ground is connected eventually to the Break pressure switch on the combination block.   If that is not hooked up, it works perfectly, if its hooked up, the system stays grounded out hence the parking brake light stays lit.

Not sure why its doing that, if I cant figure it out, I will cut the wire from the dash and run that right to the ground.
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: banshee58316 on May 01, 2012, 08:41:28 am
Check your the front signal/marker light bulb socket. I had this problem and it drove me crazy trying to figure it out. My lights would work correctly until I turned my headlights on. All the lights would dim and my signal markers inside would stay lit up green. It turned out to be the the long grounding tab that touches the bulb in the bulb socket, it was broke off and was not grounding. In my situation both sides were broke left, and right.  Be sure to take the bulb out and look because in my situation it looked like the grounding tab was touching the bulb, but in reality it was not. Cost me $6.00 to fix.

Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: jaredts on May 01, 2012, 04:50:28 pm
The brake light on the dash comes on either with the parking brake applied via a switch there, or if the wire to the combination valve is grounded.  If plugging in the combination valve makes the light come on than its probably doing its job--warning you that either the front or rear circuit has lost fluid pressure.  The other possibility is that the spool in the valve is seized to one side.  You need to do some brake troubleshooting as I wouldn't personally disable that safety feature.
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: ralphhemi on May 01, 2012, 05:29:06 pm
 More than  likely its a bad ground in the park and turn signal socket, i have also seen a bad bulb where one of the filaments brake off and ground to the other filament.
Title: Re: Trucks together....couple of electrical issues looking for advice on.
Post by: bake74 on May 01, 2012, 06:42:58 pm
     banshee58316, I saw that was your first post, welcome to the site.