Why Does Trailer Brake Controller Send Low Power with Brake Pedal but Not Override

Question:

I have a 2018 f350, when testing the brake controller at the trailer plug with a multi meter I get 13.5 amps, when I test amps just from the brake pedal at the trailer plug . I get 4 amps. This seems low to me like shouldnt the brake pedal amps be 12 or more?

asked by: John K

Expert Reply:

In regards to testing a trailer brake controller, if the controller is proportional, the brake pedal won't send full power to the trailer brakes while the vehicle is stationary. This is because proportional controller's work off inertia which is not present while the vehicle is stationary therefore, you won't see full power. That said, you should see full power (12+ Volts) while the vehicle is stationary using the override feature since it bypasses the brake pedal activation. If the controller is time delayed however, then it would indeed indicate a problem but the vast majority of times, it's the former that's the issue.

expert reply by: Conner L