Why Won't Brake Controller Work with Brake Pedal of Vehicle

Published 12/14/2022

Question:

i have checked for power to the controller it has power i plug in the trailer the light is green i turn the knob fully clockwise light stays green i press the pedal still stays green i checked for signal on the red wire no signal i press the brake there is signal i pull the manual lever to the left the light turns red i hear the power at the brakes ,can you help me know why my light doesnt turn red when i turn the knob all the way to the right and press the pedal? thanks

asked by: Chris

Helpful Expert Reply:

Sounds like the stoplight circuit of your vehicle is not connected to the red wire of the brake controller or the signal is not making it to the controller somehow. This could be due to a wiring issue like a cut wire or a connector not used properly or it can be a blown fuse on the vehicle. Typically this is the third brake light fuse of the vehicle or CHMSL. This especially likely if it's a GM truck.

expert reply by: Jameson C