Troubleshooting Trailer Running Light Circuit Remaining On When To Vehicle is Off

Question:

I bought and installed the CURT 56407 Vehicle-Side Custom 4-Pin Trailer Wiring Harness. The problem I have is the tail lights remain on even when the jeep is off. I have went through all the wiring and is installed per the video and instructions. Can you tell what the issue maybe? Thk.

asked by: Alan B

Expert Reply:

Usually when we see this problem it's because the trailer has LED lights and there is just enough power on the light circuit to light up the trailer function even though it shouldn't be.

I would start off by unplugging your trailer and seeing how much power is on the running light circuit for the Curt T-Connector # C56407 (see photo). If it's full-blast 12V power then that's an issue and there's either an issue with the Curt module or the wiring on your Jeep.

If there isn't much power then you should be able to just pop a load resistor like part # DI34ZR on that circuit to get the power to stop flowing. The load resistors basically make it look like the LED lights are pulling more power than they should so the tow vehicle will completely shut off that circuit.

Attached is a wiring troubleshooting article for you to check out as well.

expert reply by: Jon G