Electric Trailer Brake Controller Not Displaying Number When Brake Pedal Applied

Updated 04/19/2017 | Published 04/18/2017

Question:

2011 Isuzu npr heavy duty Trailer breaks are working, but when I press break pedal on truck the break controller doesnt display the number of force applied.

asked by: Clint

Expert Reply:

The most probable cause for not getting a display when you apply the truck brake, but getting a display when manually activate the override is a bad connection in the stop light circuit. The stop light circuit is the red wire coming off the brake controller that goes to the cold side of your brake pedal switch. It may still be working on the trailer in part because the inertia sensor may still be working in the brake controller.

I recommend using a circuit tester like # PTW2993 to check the stop light circuit for function when the pedal is pressed.

expert reply by: Jason S