Troubleshooting Trailer Lights Not Working When Headlights are Turned On

Updated 10/21/2019 | Published 10/19/2019

Question:

I bought the t connector for my 2012 jeep liberty. I hooked everything up just how the instructions and video showed. After getting it wired up the only thing that works on the trailer are the running lights when my headlights are on. I changed ground locations 3 times and there was no change.

asked by: Matt

Expert Reply:

Thanks for the purchase of the Curt T-Connector Vehicle Wiring Harness # C56334 for your 2012 Jeep Liberty and from how you phrased "the only thing that works on the trailer are the running lights when my headlights are on" and the fact that you mentioned changing ground locations, it seems like the trailer lights work normally except when your headlights are on.

You were smart to try and change the ground wire location to make sure it is attached to a clean, bare metal surface. Assuming that you do, the only other issue that it could be is a potential overload, as your trailer lights may be drawing more amps than the harness is rated to handle (3 amps per circuit stop/turn and 6 amps per circuit for the tail lights). The best thing to do in this situation is removing some of the clearance lights if you can, or switching to LED lights on your trailer, which take up just a fraction of the amperage of incandescent lights.

I have added a link to our selection of LED trailer lights, as well as a link to a help articles on trailer wiring troubleshooting which I highly recommend checking out.

expert reply by: Kyle S