Why am I Only Getting 9V Output From My 7-Pole to 6-Pole Adapter

Question:

My trailer plug from the motor coach only shows 9V output and the tow vehicle lights are not working even with an alligator clip connection directly from the ply to the plug on the tow vehicle, but the tow vehicle plug works fine when alligator clipped to the battery. Why do I only have 9V output from the coach?

asked by: Paula B

Expert Reply:

It sounds like there may be an issue with the wiring, either a bad ground, broken wire or corroded trailer connector.

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.

Check the wiring for any broken or loose wires and repair as needed. On the tow vehicle you can check the owners manual for the locations of any fuses or relays related to the tow package wiring. I have also included a link to a help article if you need to test the vehicle side connector.

expert reply by: Thomas M