Troubleshooting Running Lights and Brake Lights Not Functioning on a Newly Rewired Trailer

Question:

I have a small cargo trailer with a flat 4 wire connector. Only the drivers side orange side light comes on. It lights up for left AND right turn signal and main lights. None of the other side or brake lights work. I checked the bulbs and I replaced all the wiring. I checked that the tow vehicle set up was working by hooking it up to another trailer at the U haul place I had that installed. Suggestions??Thank you

asked by: Catherine B

Expert Reply:

Since the circuits that are giving you problems are related to the circuits that draw the most amperage to illuminate it makes me think that your grounds aren't quite strong enough for your setup. I would verify that all of the light assemblies are connected to clean metal surfaces if they ground through their mounting hardware.

Also, make sure the main ground from the trailer 4-way is connected to a clean metal surface on your trailer frame.

I attached a couple FAQ articles that you may find helpful as well.

expert reply by: Jameson C