Troubleshooting Trailer Lights Not Working When Connected to One Truck But Work on Others

Question:

trouble shooting trailer connection on 2017 ford f250 super duty. 7 way Trailer lights do not work when hooked up to my 2017 f250 but they do work when hooked up to different vehicle. Other trailers with 4 way hook ups do work on f250. I am stumped.

asked by: Kenneth G

Expert Reply:

That's pretty interesting but the key is that you said the trailer with a 7-way does not work with your 2017 Ford F-250 with a 7-way. If that is the case, but they work with other vehicles, and trailers with a 4-way work with your F-250 the issue is you have a poor or corroded ground pin on the 7-way of your F-250, or the ground to the vehicle (or possibly trailer frame) for the 7-way needs to be relocated to a clean, bare metal surface. If the ground issue is in fact on the 7-way of the truck, that would explain why the trailers with a 4-way would not be affected.

I have added some links to help articles on trailer wiring and troubleshooting which I also recommend checking out.

expert reply by: Kyle S