Right Brake Light not Working on Trailer

Question:

Brake light, I have a 2004 great Dane trailer service lights work turn signals work, left brake light works,right brake light will not work. Service light works on right brake light. Thank You

asked by: Gary C

Expert Reply:

This sounds like a ground problem. When proper connections aren't made with grounding, it usually results in some functions working and others not.

To resolve this issue, you need to first check the ground wire connection on your trailer. Make sure the connection is at a paint-free, rust-free part of the trailer's frame. If you find any paint, corrosion, or rust between the connection, move that connection to a cleaner spot. The key is to make as clean a connection as possible to the trailer's frame.

If you've done this and the problem persists, trace the trailer's wires to ensure there are no frays in the wiring. If there are, you need to replace that wire. You can use # 10-1-1. It's sold by the foot.

If the above do not solve the problem, you need to check the vehicle side. Use a circuit tester like # PTW2993 on your harness to ensure each function is working properly. If one is not, then you may have a blown fuse or there is a grounding problem on the vehicle. Check the connections and wires like the above steps for the trailer. If those are fine, check your fuse box for any blown fuses.

I've attached a help article that can give more detail on how to troubleshoot wiring.

expert reply by: Kef G