Trailer Brakes Stay Locked Up Unless Trailer Battery is Disconnected

Updated 05/17/2016 | Published 05/13/2016

Question:

Pulling with 2013 2500 doramax gmc. The only way I can get the brakes to unlock is to unhook the camper battery.

asked by: Larry F

Expert Reply:

It sounds like your trailer might have a breakaway system and the pin is pulled out of the switch. that would complete the circuit from the battery to the trailer brakes. That would explain why the brakes release after you unhook the camper battery. Inserting the pin back into the switch will stop that from happening. You can also replace the switch using # HM20010.

It is also possible that there is a short somewhere and battery power is feeding to the trailer brakes. You can inspect the wiring and fix any broken or pinched wires. I also recommend making sure the trailer connectors are clean and free of corrosion in case the issue is inside the trailer or vehicle side connector.

If you look at everything that is connected to the trailer's battery and inspect the wiring you will eventually find the source of the malfunction.

expert reply by: Michael H