Tips for Finding Brake Controller Stoplight Circuit Wire in Truck

Question:

I need to install my electric brake controller on a 1995 GMC 1500. I am having the damest time figuring out which wire to tap into on the brake switch. Can I add a fuse tap on the fuse block for the brake lights and run the wire from there? It seems that the one wire I did tap into at the pedal switch makes the trailer brakes fully lock when the pedal is pressed no matter how I adjust the controller.

asked by: Matt L

Helpful Expert Reply:

All you need for the red wire of your brake controller is a circuit that sees voltage only when the brakes are applied. If you wanted to run a wire to the fuse box to find a wire like you said that would work fine. Some people will also use the third brake light circuit as well.

It almost sounds like you are running the blue wire of the controller to the stop light circuit if the brakes lock up when you tap them. Or your brake controller is just set too aggressively.

I attached a help article for brake controller installs for you to check out as well.

expert reply by: Jameson C