Electric Trailer Brakes Lock Up While Connected to Tow Vehicle

Question:

My electric brakes, after a heavy rain, are staying engaged all the time. I disconnected the breakaway switch by cutting a wire, and they still stay engaged. The only way to disengage the brakes so I can pull is to disconnect from the trailer batteryand truck power. Is there a board all the wires connect to that might be fried or do I need to look somewhere specific? I have no idea where to find the connection point for all the wires, but Im looking for someplace to start. I have a 5th wheel travel trailer from 1990, Lynx Prowler.

asked by: Keegan

Expert Reply:

There appears to be a short between the brake output wire and the 12 volt power wire either on your trailer or tow vehicle. This is why the issue is only occuring while connected to the tow vehicle. Unfortunately, the brake output wire goes from the brake controller in the vehicle all the way back to each braking assembly and the 12 volt power wire goes from the fuse box all the way back to the trailer battery. The short could be anywhere on these two wires so I don't have an exact place for you to look unfortunately.

However, in order to save time you can hook up your trailer to a different tow vehicle or your tow vehicle to a different trailer as that would then allow you to determine which side the issue is occuring. The other thing you can do to save time is inspect the trailer connectors first to make sure there isn't any corrosion inside the pins. If there is clean it out with electrical contact cleaner and then use dielectric grease part # 11755 between them. Also if this is your first time pulling the trailer make sure the black and blue wires are not reversed at the trailer connector. Once this is done the only other option you have is to begin tracing the wires back and repairing or replacing as needed until the short is found/fixed.

expert reply by: Conner L