JNB
Senior Member
Hoping you can help me on this one. We are trying to hook up my tag trailer's electric brakes to my air brake equipped dump truck through a large HD 7 way round pin connector. We have the controller's brake wire is connected to the center pin on the connector and the power and ground wires are connected directly to the batteries. With or without the controller in the mix all lights and functions work but the trailer brakes are locked up until the trailer is unplugged. We installed a Hopkins digital brake controller which functions properly and applies the trailer brakes with the pedal when the key is turned off. When the key is placed in the on or run position, the controller's display disappears, the "connected to trailer" light turns off and the trailer brakes are locked up. In the on or run position the test light still shows the brake connection at the controller's red "activate" wire functioning properly when the brakes are applied or released. It's like I'm visiting backwards world...Any ideas?