Electrical Problem to Stump the Experts!

[Riley P]

Good Day,

I realize this is a Corvette Forum but I believe we have some smart people on here and hope someone can solve this issue.

The vehicle: 1985 GMC S15, 2.5L Auto 4x4.

I just got my truck from storing it at a friends place (thanks TaylorSK8!) and it was sitting outside for a year or so.

I put a new battery in it, it fired right up however on the way home,

- I have no tail lights
- I have no brake lights
- I have no reverse lights
- I have no signal lights

But!

- I have Hazard lights when the head light switch is on!

Fuses check ok. I'm going to see if the fuses are even getting power today....and then? Chasing wires?

If anyone has a suggestion to shorten the repair time, I'm all ears!

 

[Keith Tedford]

Electrical Problems

As often as not, when you have weird electrical problems, it can be traced back to bad grounds, frame, body, etc. Guys with old Chevelles run into this quite often. Of course it could be something else but the grounds are just a good, relatively easy place to start.

 

[buckhorn76]

see if you can come up with a schematic. check to see any circuits that run through relays. many years ago i had electrical woes that were traced to a bad horn relay !!! good luck , doug.

 

[Riley P]

HA! Horn relay. Crazy!

Nothing through relays that I can see..... First I'm going to check that all the fuses are getting power. If so I can start from there and check all the grounds. I don't think it's the headlight switch. I have something in parallel with the hazard/turn switch called the convenience center, whatever that means so that might be an issue?

 

[CCO]

If you have power, and no fuses are blown, it sounds like a bad ground in the rear somewhere.
G/L Riley.

C.

 

[FordPrefect]

mice ate your wiring?

 

[Case75]

I vote for ground problem. This summer after doing some work on the heater controls in the center console on my '75, I discovered that when I turned my lights on the shift indicator light would go out when the car was running and then the light would come back on when I turned the lights off. If the car was not running, the indicator light worked as it should, off when the lights were off and on when the lights were on. Upon further investigation, I noticed that the cigarette lighter lamp was doing the same thing. Both of these lamps use the trim surrounding the shifter for ground. Pulled everthing on the console apart and found a loose ground wire. Tightened it up and everything worked normal again.

 

[Riley P]

Da-da-da-DAAAA! Ground!

There was a broken ground wire in the back harness. You could hardly tell though because it only came out of the conduit about two inches and didn't look like it attached to anything! Well, using a test light, then alligator clips, wal-lah! All the lights in the back work. It's unbelievable as it's such a small ground wire. What a weird, weird issue. Anyway, here's a pic of the general ready for duty!

 

[Case75]

Glad it worked out for you Riley!

 

[Woodstock Car Guy]

Congrats on your ability to locate the problem.

 

[Riley P]

Thanks very much guys! I knew....or a least hoped it couldn't be that difficult to find. It's just so funny that one set of lights worked and other sets did not. I thought the wiring would be fine as the lights did light up but there you go! Grounds really do weird stuff.
One more pic from when I finished doing the body five years ago.

 

[Steamer]

Riley, glad you found the problem. But tell me, what's going on with the Wacky Khaki and the NATO star on the back?

 

[Riley P]

Well, about 5 years ago my truck was nearly wasted away. I got my hands on a whole bunch of body parts and instead of painting it black again, I figured I would do something funner and make myself a little army truck since I always wanted one. I like the star as that is what I grew up with seeing on all the army toys. I realize it's an American symbol but it's more widely recognized than the Canadian symbol and I don't want to replicate a real army vehicle, just the army vehicles that I played with. I also put registration numbers across the roof, but they're there for fun too and don't follow the military protocol.

However, now that I am married, the paint is lifting and rusting underneath because it didn't cure properly, I'm going to repaint it by going to POR-15 black!

 

[taylorsk8]

I pulled it out on purpose just to see how smart you were. I guess you passed the test!

T

 

[Riley P]

I knew it! And what a wire to pull out! It didn't look like it as attached to anything!

 

[Steamer]

Riley if I knew you wanted an army truck I would have sold you this one.

Ultimate party vehicle. Put 20 people in the back, 400 gallons of beer in the tank and point it were ever the want to party and just mash the throttle.
1955 GMC M135CDN 302 cu. in. six cylinder 40 MPH, up hill, down hill or on the flat, didn't matter!!!

 

[CCO]

Riley if I knew you wanted an army truck I would have sold you this one.

Ultimate party vehicle. Put 20 people in the back, 400 gallons of beer in the tank and point it were ever the want to party and just mash the throttle.
1955 GMC M135CDN 302 cu. in. six cylinder 40 MPH, up hill, down hill or on the flat, didn't matter!!!

Hey Rob did you have the artillery attachment too????

C.

 

[Riley P]

That is EXACTLY what I wanted as a kid! That would have been awesome!!!!!

 

[Steamer]

Sadly the old girl is leaving for a new home this Sunday. It's time for new chapter in her life. I was never able to find a surplus 105 howitzer for it to tow, but I did have one hooked on the back once at an airshow!

 

[67HEAVEN]

...I was never able to find a surplus 105 howitzer for it to tow...

Well thank god for that.