Problem with turn signal with lights on

[Bulldog]

I'm working on my 1987 Chevy 1/2 ton truck.

The turn signals work fine without the marker lights turned on. With the marker lights turned on, the left signal works fine but the right signal will just stay light solid. If I try the hazards, they will light solid on both sides. With marker lights off, when I hit the brakes all the marker lights will come on.

I checked all the bulbs, only found two marker lights burnt out and replaced those. Still have the problem. I changed all the signal, marker, brake and reverse light bulbs and still have the problem. I installed a new flasher and still have the problem. I cleaned the ground at the back of the truck near the bumper and at the front of the truck on the radiator support and still have the problem.

I think it's a grounding problem, but am not sure. What other things can I look at?

[ak_petey]

sounds like it is a ground somewhere, I would check for frayed lines, or even live wires tied into the problem bulb.
could it possibly be marker light wire tied into a signal light wire that is not grounded? That would be my guess

[ChevyKev]

Possible grounds.

More probable to me would be a short between wires somewhere. 24 year old vehicles can tend to get shorts between cracked or frayed wiring. Unfortunately - I've seen a lot of this happen in the column, which is a pain to get into and replace.

CA - I sent you a PM as well.

[akcowboy76]

I would check for shorts behind the gauge cluster and clean every ground on the truck. I have had this on other rigs in my past and found it in the dash not having a good ground.

[Bulldog]

Donald was able to come over yesterday and do some troubleshooting/repairs. Thanks Donald. He traced the cause of the problem down to my trailer wiring harness. He disconnected it and everything worked fine. I'll have to troubleshoot this and find the cause when I get home (Donald I'll let you know what I find). During his troubleshooting, he also found two light sockets that had bad grounds. They were able to change one out and my son was going to pick up the other one today. Thanks again Donald.

[88XJ]

No Problem.