Troubleshooting Dim Trailer Lights that Go Out Completely When Stepping on Brakes

Question:

The lights are dim and when step on brakes lights go out

asked by: James B

Helpful Expert Reply:

It sounds like you have a classic ground issue on your trailer that is preventing proper voltage from reaching back to the tail lights.

What I recommend doing is first making sure the main ground for the trailer connector is secured to a clean bare metal surface. Then you can go back to the light assemblies themselves to make sure they are grounded in the same manner. Depending on their style your lights may use a separate ground wire or they might ground through their mounting hardware. In either case make sure they are attached to a clean bare metal surface that is free of any debris or corrosion.

If all the grounds look good or you have relocated them and the issue persists then your next step is to inspect the wiring for the brake/turn signals on the trailer for any pinched or exposed areas that need to be replaced.

Please let me know if you aren't able to resolve the problem and we can continue to troubleshoot.

expert reply by: Chris R