Left Brake Light Not Working On a 14 Foot Utility Trailer Pulled by a 1999 Chevrolet Silverado

Question:

1999 Chevy Silverado. 14 Utility trailer. All lights work except left brake light, which goes out completely when brake applied. Release brake and running light comes back on. Please provide possible problems. I seem to be grounded well on the trailer. I believe light housings are grounded internally.

asked by: Nathan

Expert Reply:

I think you have started in the right direction. Tail lights are not internally grounded and must be grounded in some way to the trailer frame. The connector on the trailer should be secured to a clean surface on the trailer frame and each taillight assembly must be grounded either through the mounting bolts or a separate wire from the taillight to the trailer frame. If there is a plastic mounting bracket for the license plate between the left side trailer light and the frame this is many times the problem.

When you apply the brakes, and the running lights are on that is when the amperage draw is the highest and ground problems show up at this time.

If all of the ground connections turn out to be good, you will need to use a circuit tester, item # PTW2993, to check the yellow and brown wires running to the left side of the trailer for a short, pinched or frayed wire that is causing the problem.

expert reply by: Robert G