re: Pulled the wiring harness from my fifth wheel

I read something about pulling the pin in the break away switch. That should apply full available voltage from the trailer battery to the brakes. If the brakes are locked up then that narrows the issue down to somewhere between the switch and your truck.

Eta it could also be the actual plug. Also reading that those plugs are sketchy. It could’ve been damaged enough to not get a good connection when plugged into your truck.