Trailer Brakes Locking up When Towing with 1987 Ford F-250

Updated 06/05/2017 | Published 06/02/2017

Question:

I just bought a 2003 Keystone Sprinter fifth-wheel. I hooked it up to my 1987 Ford F-250 HD diesel and plugged the power cord in; the brakes locked up and my brake controller got hot. Needless to say, I towed it home with no brakes. I bought my truck used with a fifth-wheel hitch and wired with new plug? Or could it be the breakaway switch? I checked the wiring and it looks like one of the wire's insulation melted a little but not bad; I think I unplugged it in time. Breakaway is a Bargman.

asked by: Michael W

Expert Reply:

The first thing to do is check the connections to the breakaway switch to ensure they are complete. After that, you will want to use a circuit tester such as # PTW2992 to check for power on your truck's 7-pin trailer connector as outlined in the help article on testing brake controls I have linked. Doing this will ensure everything is operating correctly with your truck and narrow the problem down.

Since you mentioned that your wires melted, that could also be an issue if any of the wires are touching; you will want to examine them to make sure they aren't touching. I've also added a link to an article on brake control troubleshooting which you may find useful.

expert reply by: Kyle S