Trailer Brake Lights Not Working on a 5th Wheel Trailer

Updated 06/18/2020 | Published 03/11/2011

Question:

The trailer brake lights wont work. All other lights work, even the signal lights which use the same posts as the brake lights. What do you think the problem is?

asked by: Terry S

Expert Reply:

What it could be is the tow package fuse or relay for the brake lights is blown or otherwise not working properly. You will need to check the vehicle owners manual and/or check the power distribution box lid to find the tow package fuses/relays in question. Add or replace the offending part and test it again. If that was the problem and it blows again then there is a short somewhere, most likely a bad ground which could be where the two connectors come together or at the trailer tail lights.

expert reply by: Michael H