Troubleshooting Trailer Running and Brake Lights Not Working After Installing New Running Lights

Question:

Our new trailer running lights are not working and neither are the brakes. Are they both connected to the same wire for power? Please help. I read the post above about what to check for running lights but what about the brakes?

asked by: Jamie R

Expert Reply:

Brake lights and running lights are not powered via the same wire.

Since you're having multiple circuits have issues I'd double check that your hooked up the main ground on the frame, and that no grounds were removed.

If grounds check out you'll have a wire coming from each running light that gets attached to the running light circuit on your trailer connector. Some lights ground through the mounting hardware so if your lights don't have a ground wire make sure you attached them to clean metal or you didn't ground them.

For the brake lights there's another wire that runs back to your tail lights, but if you have turn signals then you should have brake lights as they are powered from the same wire, which is why I think you have a ground issue as they cause all sorts of weird stuff.

I went ahead and included a help article link below that goes over wiring for you to check out as well.

expert reply by: Samuel C