Trailer Lights Not Working After Installing Trailer Wiring Harness on a 2010 Jeep Compass

Question:

Got the harness installed and all the lights on the vehicle work, no problem, but I getting nothing on the trailer lighting. Could it be a bad ground connection?

asked by: Barry K

Expert Reply:

It very well could be a bad ground connection between trailer wiring harness # C55050 and your 2010 Jeep Compass. Make sure that the white ground wire is attached by itself to a bare metal surface. No paint or coating can be on the ground location surface.

Also make sure that the fuse is inserted in the included fuse holder and that it is not blown.

If the trailer lights still do not come on, then use a circuit tester such as # PTW2993 to test the 4-Way end of the harness while someone goes through the lighting functions. If you do not have power at the 4-Way, then it is likely a problem in the converter box and the harness will have to be replaced.

If there is power on the vehicle side 4-Way, then the issue is on the trailer, likely a bad ground or corroded trailer connector. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light but can show up any time.

Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces.

The light grounds should also be attached to clean and corrosion free bare metal surfaces. If there is anything between a light ground and the metal trailer frame or if the trailer has an aluminum frame, tilt bed, or folding tongue, any of these things can interrupt the ground. Running jumper wires from the light grounds to the main trailer connector ground can help.