Trailer Brakes Activating With Brake Pedal Is Pressed With No Brake Controller Installed

Question:

Should the trailer brakes get power without a controller hooked up? I have a 2007 Ram 1500, am having trouble getting the controller to show trailer connected, but when i completely disconnect the controller, the trailer brakes lock up when i apply the truck brakes.

asked by: Brandon

Expert Reply:

If you're getting voltage to the trailer brakes with no controller installed, and when it WAS connected it wasn't reading the brakes, it sounds like your trailer connector on the vehicle is either damaged or has had corrosion spread to the terminals inside where the wires attach. Once the terminals corrode, the corrosion builds up can can actually allow adjacent circuits to bridge which would explain why you get brakes without a controller installed. It's possible that the brake lamp circuit and possibly the 12-v circuit for the trailer is applying power to the brake output circuit.

If you find that the trailer connector is damaged or corroded, you can replace it using part # HM40975-11933.

expert reply by: Mike L