Troubleshooting Trailer Wiring Issue with 2008 Jeep Liberty

Question:

I have a 2008 Jeep Liberty. I have installed a Curt # 55027 wiring package. Ordered from etrailer. All lighting works fine on vehicle. The turn/brake lights work on the trailer until I turn on the headlights on the vehicle. I only get a bright light on drivers side trailer light then. Vehicle lighting works. Have double checked ground. Now what?

asked by: Bob P

Expert Reply:

The fact that your trailer lights seem to work just fine until the vehicle headlights are switched on indicates a ground problem somewhere in the system.

The quick way to confirm a ground problem would be to disconnect your existing ground connection from the trailer and use a butt connector to temporarily connect a length of wire long enough to reach the negative battery terminal. If this temporary jumper fixes the problem (which it most likely will), you have confirmed a poor ground as being the cause of the problem.

There are also other grounding points to check. Not only does the ground wire from the trailer connector need to ground directly to the trailer, typically on the trailer tongue somewhere, but the connector on the vehicle also needs to be grounded to the vehicle frame, if it has a separate ground connection wire. If you are using an adapter like the # 37185, make sure its ground wire is securely connected to the vehicle frame. Make sure each lamp is properly grounded, either by its physical connection through its mounting studs to the trailer frame or by its separate ground wire. If the lamps depend on their mounting studs for the ground connection and they are mounted to a wood or plastic portion of the trailer, a jumper wire will need to be ran from one of the studs to the trailer frame.

Sometimes the actual design of the trailer itself causes the problem. A trailer with a folding or tilting tongue or a tilt bed will depend or one or more hinge or pivot bolts to transfer the ground connection from the moving to the stationary portion of the trailer. This works well enough when the trailer is new and everything is tight, but after a few years these pivot points wear and the connection does not remain reliable. Running a simple jumper wire (a length of wire with a ring terminal on each end) to join the moving and stationary portions of the trailer will solve the problem.

I have linked you to our Trailer Wiring Troubleshooting FAQ article, which you might find helpful.

expert reply by: Mike L