How to Supply Power to a Trailer to Test Wiring

Updated 05/18/2019 | Published 05/17/2019

Question:

On my truck I have a 7 way plug which I plug my 6 way plug from my gooseneck trailer into. Would this tester help me to diagnose a problem on the trailer side? Thanks

asked by: Bill

Expert Reply:

In order to test a trailer you need something like the Tekonsha trailer wiring tester, part # 8010. It's designed for trailers with a 7-way connector but you can use your adapter from your 6-way just like you plug it into your truck.

Another way to test a trailer's lights is to get a standard vehicle battery. With the battery fully charged, connect a wire to negative post and ground it to a good bare metal location. Then connect a wire to the positive post and use it with each function on the trailer to test them one by one. You can also plug the trailer into your truck like you normally would when towing and have someone go through the lighting function in the truck while you test each circuit on the trailer individually.

expert reply by: Charles S