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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: Burgersquatch on November 28, 2012, 11:57:12 am

Title: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: Burgersquatch on November 28, 2012, 11:57:12 am
Hi all, new to the forum (first post)... recently got myself a 1973 K10 stepside and a couple issues have come up.

When I first bought the truck, all lights worked except the front passenger blinker (rear worked). I just moved from the western foothills of the California Sierras to South Lake Tahoe and now my pass-side brake and blinker stopped working, as well as the driver-side reverse light. When it was just the pass-front blinker, I tried those bulbs (front/side) on the driver side and the bulbs worked/flashed fine... now both pass-side blinkers and brake light don't blink or light up (running lights do work). From the inside of the cab, the right directional indicator light would flash, but not since the rear blinker quit, now it does nothing (left works).

I just replaced the bulbs for the driver-side reverse light and pass-side brake light... running light still works, no reverse, blinker or brake.

I haven't gotten to fuses yet. Should have picked some up when I was at the parts store yesterday but whatever, I'm stopping in on my way to work today. I've found the blinker fuse, which works for the driver's side... can hear and feel it clicking. Does that fuse have a separate driver/pass function? Like, could half of it go bad causing the blinkers to quit on one side? Or, if that fuse went out, no blinkers would work?

I assume that after replacing the cheap and easy stuff (bulbs/fuses) that if it still doesn't work, I have to go over connections and chase wires. I'm just trying to get some input on my situation, collect info and maybe find someone knows something that will make my life easier. Also, the sooner I can get my lights back on, the sooner I can stop worrying about getting pulled over and ticketed.

All help is greatly appreciated!

Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: zieg85 on November 28, 2012, 12:04:20 pm
Does your emergency flashers all work?  That would indicate if the trouble is in the wiring or the turn signal switch itself...
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: zieg85 on November 28, 2012, 12:04:51 pm
Forgot to say Welcome from NW Indiana!!!
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: Burgersquatch on November 28, 2012, 12:27:32 pm
Only/all driver-side lights/indicators blink (front, back, dash). Nothing on the passenger side.
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: bake74 on November 28, 2012, 07:25:54 pm
     Welcome from Sac., CA.  I have a 74 k10 step side that I retrieved out of a field 2.5 years ago.  I had issues with the lights after a couple of months.
     A few things I found.   Make sure your grounds are good.  Check at each light bulb for corrosion, this was a headache for me and took a couple of nights to track down the symptoms.  I found them by checking dc volts at each source, and sometimes I would get power and some times not, then I cleaned everything real good and got rid of the corrosion and no more problems so far.
     Good luck and keep us updated.
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: Burgersquatch on November 28, 2012, 08:31:06 pm
Time to see if I know anyone with a voltmeter. Unless I can find one for cheap.

Also thinking about just picking up a full set of bulbs and fuses... pretty sure I'll need 'em at some point.
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: pholliday1 on November 29, 2012, 04:37:53 pm
Grounding is a big issue for our trucks.The oem screw through the metal leaves alot to be desired. A multimeter will be your friend in this case checking voltage, ground and continuity. Also I have had several sockets be bad for no apparent reason have power and ground in the socket but not able to get bulb to make the right contact. I have found it also useful to run a dedicated ground wire to the rear and solder my grounds in that way.
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: pholliday1 on November 29, 2012, 04:39:18 pm
Forgot like Zieg....Welcome from Northern NY
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: Burgersquatch on December 02, 2012, 01:13:02 pm
Thanks so much for the info guys, really helps my stress levels knowing there's someone who knows what they're doing.

Still haven't gotten into it, haven't found the time or a multimeter yet. Busy trying to make money and keeping the tattoo shop I apprentice at, happy. So far, so good... but I'm on a pretty tight budget.
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: Jason S on December 03, 2012, 02:27:41 am
Howdy from Oklahoma.

Like Zieg and pholliday said, check your grounds.

Most auto parts stores should have a relatively inexpensive multimeter in stock, usually under $20. Sometimes pawn shops will have better multimeters for a decent price.  A digital or analog will work for this.
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: Burgersquatch on December 03, 2012, 02:35:48 pm
Stopped at O'Reilly on the way to work to pick up a flasher fuse, popped it in and did nothing. At first.

So after the fuse failed to be an instant successt, my truck wouldn't start. Something likes to stick and flood (http://forum.73-87chevytrucks.com/smforum/index.php/topic,25039.msg208892.html#msg208892 (http://forum.73-87chevytrucks.com/smforum/index.php/topic,25039.msg208892.html#msg208892)). I should really get my (only) mechanic friend to give me a hand and check the plugs and points, I wouldn't be surprised if something has fouled. I'm thinking the idle might need to be turned up a hair... idles fairly low and in the cold it seems to starve a little until it warms up or is driving down the road. I just need to hit up a thrift store or two and see what I can pick up for cheap tools.

Anyway, while the carb was draining of fuel I went back inside and borrowed a multimeter. They had a cheaper yellow one for like $15 but I'm on a tight budget and want to see if I can find something cheap-cheap. Took me a minute to figure out how to test the connectors but I eventually turned the hazard flashers on and checked the driver's side that works against the passenger side that doesn't. The numbers jumped from about 4.5v to 8 or 9, depending on the blink. With the hazards still on, I started to replace the PS bulb and it started flashing when I pushed it into the socket but stopped when it was fully locked. I backed the bulb out of "lock mode" a hair, so the connection was stiffer and it stayed working. Put the lens back on and still worked. I was by myself and wasn't able to check if the brake light also lit up. I'm at work now and will have someone check it before the end of the day.

I still have a PS flasher, DS reverse bulb and plate light to troubleshoot. The rev bulb has been replaced but I couldn't check the power cuz I think the truck needs to be running, with someone inside holding the clutch with the truck in reverse. I couldn't get a reading with the ignition power on (motor not running) and the trans in reverse (no light, either side). The PS front running lights work but the PS blinker don't blink. I needed to get to work so I didn't bother messing with it, got the truck running and left. I haven't touched the plate bulb yet, I recently found that wasn't working.
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: bd on December 03, 2012, 04:08:39 pm
Make sure you have the correct turn signal/park/tail lamp bulbs installed - all four corners use an 1157 bulb (interchangeable with a 1034).  If the wrong bulbs are installed, the contacts may not line up correctly.  Make sure the sockets are clean, then coat the base of the bulbs with some non-conductive white grease to protect the connections from corrosion.
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: Burgersquatch on December 03, 2012, 04:29:05 pm
I looked up the part #'s for the bulbs and used some dielectric grease. The only bulbs I purchased were for the brake/blinker and reverse. The reverse bulb only has one contact vs the 2 dots on the flashing bulbs. I'm thinking the contact plate inside the socket might have gotten turned a little or perhaps whatever holds tension against the bulb has gotten weak and not applying enough pressure.
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: pholliday1 on December 04, 2012, 08:33:58 am
As for checking brake lights , when you need a phantom brake pedal pusher just cut yourself a short 2x4 to wedge between seat and fully depressed brake pedal. I also keep this board under my seat when i am winching and need a little holding power.
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: bake74 on December 04, 2012, 06:37:58 pm
I looked up the part #'s for the bulbs and used some dielectric grease. The only bulbs I purchased were for the brake/blinker and reverse. The reverse bulb only has one contact vs the 2 dots on the flashing bulbs. I'm thinking the contact plate inside the socket might have gotten turned a little or perhaps whatever holds tension against the bulb has gotten weak and not applying enough pressure.

     On your bulb sockets, the single bottom point you mentioned.  Have you checked to see if that single point on the bottom side ( or back side ) is not corroded where the wire attaches to that single point ? 
     On my 74 if I remember correctly I had to fix a couple of these connection points and wires.
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: Burgersquatch on December 06, 2012, 12:59:29 pm
On your bulb sockets, the single bottom point you mentioned.  Have you checked to see if that single point on the bottom side ( or back side ) is not corroded where the wire attaches to that single point ? 
     On my 74 if I remember correctly I had to fix a couple of these connection points and wires.

I haven't gotten to any socket wiring yet. And without the truck running and in reverse, I couldn't get any power to the reverse lights to test them.
Title: Re: 73 K10: Blinker, Brake and Rev Light Issue - HELP!
Post by: Jason S on December 13, 2012, 09:32:34 pm
If you turn the ignition to the "ON" position (just before the start position) that would provide power to all the circuits without the engine running. Set the parking brake or chock the wheels and then move the transmission position selector to "R" to run your tests.