Tail lights not working
I have a '94 z71 stepside I am having electrical problems with. When I turn on my headlights, I lose brake lights and tail lights. Also when I press my brake pedal, my turn signal speeds up like I have a bulb blown. All fuses are good to my knowledge plus I don't think this could be a fuse since so many different circuits are involved. The stereo was stolen out of this truck before I purchased it but it looks like the factory wiring harness was left in the truck. I have not replaced the stereo as of yet. Could this be caused by the turn signal switch since all systems seem to run through this or something else? Any help would be greatly appreciated. Also, there is some aftermarket wiring in place for a stereo amp and a CB radio. I have visualized the wiring for these the best that I can and have not found any bare wires or shorts. Thanks again for the help.
Welcome to the club.
I think you have a ground problem, and, I think it is in the rear of the truck.
All rear lights are connected to ground, as long as there is not a lot of current flowing through the poor ground, one set of lights will work, add the current flow for a second set and the ground resistance increases and slows the current.
As it appears common to all lights at the rear, I suspect the bed to chassis ground strap.
Bad grounds will play havoc with all kinds of systems. You're lucky that only your lights are being affected right now. If you find and fix the bad ground, you not only could fix the lights, but hold off any other problems that may be developing due to voltage fluctuation issues.