Troubleshooting Vehicle 4-way Connector Having No Ground When Plugged Into Trailer

Question:

Hi, I have rewired a trailer with a standard 4-pin connector. The lights are self grounding to the frame, so 2 wires from each light. I did a test by connecting the one side to the new trailer connector as instructed. Yellow-yellow and brown-brown driver side. White is grounded to the tongue. Now when I connected to the car, I got no power. Using a meter, I ONLY get power from the car connector if I ground to the chassis, not to the connector. The issue is that this happened ONLY after I did the trailer test. I had good grounding from the car connector before the test? Any ideas. thanks

asked by: :uc

Expert Reply:

Since the ground issue on the 4-way connector on your vehicle only occurs when the trailer is plugged in, it sounds like the trailer ground is bad.

First I would make sure that the main ground to the tongue of the trailer from your new 4-way connector is secure to clean corrosion free metal.

Next if your trailer has an aluminum frame or a tilt bed you will likely need to run jumper wires from the mounting hardware of each light to the main ground on the tongue, as these style trailers have a hard time getting a good ground.

To do this I recommend # 16-1-1 with ring terminals # DW05737-1.

I included a link to a helpful article on wiring for you to take a look at.

expert reply by: Samuel C