Troubleshooting Trailer Wiring That Only Works on One Side at a Time

Question:

We rewired our trailer with a kit when connected to one truck left side works not the right when connected to different truck right side works left side doesnt what have we done wrong

asked by: Melissa

Expert Reply:

Sounds like you might have a weak ground for the trailer lighting circuit and that's why only one side of the lights will work at a time. Best option would be to try improving the grounds on the trailer lighting to see if that fixes the lights. If the lights ground through the mounting hardware make sure the trailer frame is clean and free of rust. Or you could also run a jumper ground wire from the light's ground back to the main ground harness of the trailer.

I attached a couple help articles on trailer wiring troubleshooting for you to check out as well.

expert reply by: Jameson C