Troubleshooting Trailer Stop/Turn Signals that Work Intermittently

Published 10/15/2014

Question:

I have a 5foot x8foot utility trailer. the runing lights work fine. my problem is some times the brake light work and some times they dont. also with the R. and L. turn signels will work fine one time and then the next time it will not. Im stumped. I am on my second trailer harnes. with no change to this problem.

asked by: Wayne B

Expert Reply:

Sounds like a ground problem on the trailer. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces.

The light grounds should also be attached to clean and corrosion free bare metal surfaces. If there is anything between a light ground and the metal trailer frame or if the trailer has an aluminum frame, tilt bed, or folding tongue, any of these things can interrupt the ground. Running jumper wires from the light grounds to the main trailer connector ground can help.

I also attached an FAQ on troubleshooting 4-way installs for you to check out as well.

expert reply by: Jameson C