Troubleshooting Trailer Running Light Circuit

Question:

I need a diagram for the tail light configuration of what wire operates what and what they connect to please??

asked by: Tressa

Expert Reply:

I've linked to our trailer wiring troubleshooting guide and to some wiring diagrams that I hope you'll find helpful.

The first step is to determine if the problem lies in the wiring on the vehicle or on the trailer. The simplest way to do this is to try the trailer with a different vehicle and the vehicle with a different trailer if possible. This will tell you immediately where the problem is.

If this isn't feasible, you can use a circuit tester like #PTW2993. Turn on the vehicle headlights and use the tester on the pin in the 11:00 position in the 7-way trailer connector. If the pin shows voltage, then the problem is in the trailer wiring. If it does NOT show power, you likely have a blown fuse. Check your owner's manual for the specific fuse location.

If the problem is in the trailer wiring, Trace the running light circuit from the trailer connector. The running light circuit is typically carried by a brown (or sometimes a green) wire. Trace the circuit back from the trailer connector, looking for pinched wires, loose or broken connections and cracked or worn wire insulation. Repair as needed.

expert reply by: Mike L