Brake lights Stopped Working, 1995 Chevy C/K Series Pickup Truck

Expert Reply:

If the brake lights are not working on the truck, try checking the brake light fuse if you have not done so already. The owners manual for the truck should tell you where it is located.

If the brake lights are not working on the trailer side but you have power to the 4-Way on all circuits on the truck side, there is probably a bad ground, loose or broken connection, between the trailer connector and the tail lights.

First, check the connectors on both sides for dirt and corrosion and clean them out. From there, check the main ground from the trailer side connector and make sure it is attached to a clean and corrosion free bare metal surface. Then move on to the tail lights.

Trailer tail lights usually ground through the mounting studs unless there is an obvious ground wire. In either case you will want to make sure there is no dirt or corrosion where the lights are grounded. If you had recently added a plastic license plate holder, it can cause ground problems too.

Another possible issue is a loose or broken wire somewhere on the trailer. You will need to test the wiring from the back of the trailer side 4-Way back to the tail lights testing for breaks using a circuit tester like # 3808 if needed.

expert reply by: Michael H