Power On Ground Wires Going to the Brake Magnets

Question:

What is a bad brake magnet ground

asked by: Joseph M

Expert Reply:

You should not have current on the brake controller's ground wire when the brakes are applied. If you do you have a bad ground or a problem inside the brake controller. Brake controllers have no user serviceable parts inside them so the best action would be to replace the controller. I recommend the Tekonsha Prodigy P3, part # 90195. This brake controller is easy to set up and is one of our best selling controllers.

If you are checking the wires at the trailer brake magnets and you have power on both the ground and hot wire when the brakes are applied you definitely have a bad ground. You should only get power on one of the wires going to the brake magnet. It does not matter which wire but only one of them, not both. You need to trace the wires and make sure the ground wires are securely grounded to bare metal on the trailer frame and that the ground at the trailer tongue is securely grounded to bare metal also. A bad ground at the brake magnets will not necessarily cause a fuse to blow or a circuit breaker to trip because the feedback is not strong enough to break the fuse or circuit.

expert reply by: Chris O