Troubleshooting Trailer Brakes that Lock Up When Trailer 7-Way is Attached to Tow Vehicle

Question:

I put a new 7way connector on my 16 ft trailer and now my brakes lock up when I plug in to my truck I dont know if I have a wire cross or if I have power going to my brakes all the time or what. But I can hook up to other trailers and dont have any problems.

asked by: Johnnie E

Expert Reply:

It sounds like you have shorted the brake output circuit of the new trailer 7-way with the 12 volt power circuit and that is causing the trailer brakes to stay on all the time. The best recommendation I have would be to go over the install looking for anything obvious that would cause a short and fix as necessary.

I also attached a diagram that shows how a 7-way should be wired as well as a help article on trailer wiring for you to check out.

expert reply by: Jameson C