Odd turn signal / brake lamp issue

[Scott Delaney]

Recently the passenger side rear turn signal and brake lamp stopped working on my 83 C20. Drivers side works fine.

The tail light lights up fine and, yes, I have the correct bulb installed. The turn signals work on the other three corners.

Where in the hell do I begin to look for this problem?

 

[78C10BigTen]

Id look for broken or burn wires near it and missing grounds.

 

[78C10BigTen]

Also, honestly as dumb as it sounds change the bulb. Ive seen where the filamemt looks intact but indeed was not. May be just that simple

 

[Scott Delaney]

Also, honestly as dumb as it sounds change the bulb. Ive seen where the filamemt looks intact but indeed was not. May be just that simple

Went through three bulbs before I finally swapped the drivers and passenger side bulbs. They are in good working order.

I also now have a few spares for the glove box.

 

[78C10BigTen]

Went through three bulbs before I finally swapped the drivers and passenger side bulbs. They are in good working order.

I also now have a few spares for the glove box.

Usually the KISS method works

 

[Matt69olds]

Push and pull the hazard switch a few times. Sometimes strange taillight issues can be fixed like this.

 

[Scott Delaney]

Push and pull the hazard switch a few times. Sometimes strange taillight issues can be fixed like this.

Gave it a shot.

No dice.

Doesn't seem to be a ground issue because all the lights in that fixture share the same ground

Seems like I've got it isolated to the yellow wire that handles the brake/turn signal/hazard filament.

I hope.

 

[AuroraGirl]

Maybe the socket is bad?

 

[AuroraGirl]

Also, when ground isnt good some of the lights work and some dont.. typically in pairs, but grounds are mysterious. I only know this because I quickly fabbed up a wire connector and just touched it to ground on various surfaces. ungrounded i got half the lighting but no function from the lights, all just lit. But once grounded the individual circuits worked properly.

 

[Scott Delaney]

Hey, thanks for all the replies and suggestions.

I started tracing the wires from the rear passenger side fixture and could not find any problems. All the wires were secured in their loom with no areas worn through or anything.

Just for kicks I disconnected the trailer wire harness (it's the kind that T's into the rear wire harness) and reconnected the two rear plugs into each other.

Bingo! Problem solved, more or less. I installed that trailer wiring harness last fall and it worked fine at the time. Maybe something got messed up on it through the winter. In any event, I'll troubleshoot that problem later when I have more time.

In the meantime I'm back on the street!

Thanks again.

 

[AuroraGirl]

Hey, thanks for all the replies and suggestions.

I started tracing the wires from the rear passenger side fixture and could not find any problems. All the wires were secured in their loom with no areas worn through or anything.

Just for kicks I disconnected the trailer wire harness (it's the kind that T's into the rear wire harness) and reconnected the two rear plugs into each other.

Bingo! Problem solved, more or less. I installed that trailer wiring harness last fall and it worked fine at the time. Maybe something got messed up on it through the winter. In any event, I'll troubleshoot that problem later when I have more time.

In the meantime I'm back on the street!

Thanks again.

When I spliced my trailer wiring in, my lights didn't function correctly when I had the main harness only grounded (touched to ball hitch) and worked normal when the trailer wiring had a good ground