Troubleshooting Running Lights Not Working On Trailer

Updated 06/19/2019 | Published 06/18/2019

Question:

every thing works except runnunig lights and tail lights I know it is the brown wire

asked by: Gloria W

Expert Reply:

The most common issue when the running lights or taillights are acting up is the ground on the trailer connector on the vehicle side. You want to make sure it is grounded to a clean bare metal surface. The next step is to check the ground on the trailer side.

If all of the grounds look okay, you want to test the taillight circuit on the trailer connector with a circuit tester like part # PTW2993. If you test the circuit fed by the brown wire with the circuit tester while the vehicle's head lights are on and you do not get power, then you may have a fuse blown. I do not know the year make model of your vehicle, but the owner's manual normally tells you the fuse locations of the lighting functions in your vehicle. You may also need to replace the trailer connector or check it for corroded/bent pins especially the running light circuit.

If you do get power at the running light circuit then you know that the issue is on the trailer side. You want to trace the brown wire back to the trailer checking for frayed or damaged wires.

expert reply by: Heather A