Boat Trailer Lights Not Working when Connected to a 2011 Mitsubishi Endeavor  

Question:

Helpful Expert Reply:

The first thing to check for a factory fuse that is missing or blown. Check the vehicle owner's manual for any and all fuses related to the tow package wiring so you can check them.

If all the fuses are good and in their proper places, then you will need to test the harness to determine if it is the problem. Use a circuit tester such as # PTW2993. Test the wiring going into the converter from the vehicle. If there is no power, there then the issue is a fuse or a wiring issue on the vehicle itself.

If it does have power going into the converter then test the wiring coming out of the converter to the 4-Way. If there is no power coming out then that indicates a problem with the harness and it will need to be replaced.

If there is power on the 4-Way end then the issue is on the trailer, likely a bad ground. 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.

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.

expert reply by: Michael H

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