Troubleshooting Weak Lights on One Side of Trailer

Question:

Hello, I have a boat trailer and the right side lights work perfectly and are bright. The left side works but is very dim, almost to the point of not coming on. I have fixed the broken/damaged connections that I can see. Would this still be a ground problem even if one side is working perfectly? Thank you.

asked by: Jonathan H

Expert Reply:

Yes. It's possible that the ground wire still isn't attached properly to the trailer frame; it should be attached to a rust and paint free spot on the frame with a self tapping screw and ring terminal for the best results. The other issue that you'll want to check is to make sure that the trailer wiring output from the vehicle is providing the proper 12v on each circuit. You can perform this test with a Digital Multimeter with 42" Long Test Leads - LED Display # PT89ZR.

If you can't locate the source of the issue with these steps, let me know and I can give you a few other things to check out. I've also linked an article on troubleshooting trailer wiring that you might find helpful.

expert reply by: Erik B