Truck's Air to Electric Trailer Brake Problem

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...

Truck's Air to Electric Trailer Brake Problem

Truck's Air to Electric Trailer Brake Problem