Testing Power to a Proportional Brake Controller

Question:

I installed a brake controller a couple weeks ago. As instructed, I connected the red wire to the brake with a 12 v output when the brake is depressed. I get anything from 0v to 3v then going to the trailer brakes. The manual control works great and is sufficient, but I get nothing from the brake itself. Any suggestions?

asked by: Randy M

Expert Reply:

Because proportional brake controllers send power to trailer brakes that is proportional to the braking force applied to the vehicle, the brake pedal can only be tested while the vehicle is moving. The brake controller will send the brakes somewhere between 0V and 3V of power when still, and the manual control will work fine when still. Before connecting the blue wire, try taking a drive while a helper tests the power output on the blue wire when braking.

expert reply by: Victoria B