Brake Controller Not Activating Trailer Brakes when Stepping on Brake Pedal in International Truck

Question:

I have an international tree truck I cannot get the brakes for the trailer to activate with the pedal any ideas?

asked by: Dustin

Expert Reply:

When a brake controller does not activate the trailer brakes when you step on the brake pedal that indicates a problem on the red wire going into the brake controller. A lot of big trucks like your International will not have a brake switch wire that you can use if the truck has air brakes. In that scenario the brake light only signal has to be obtained elsewhere such as at a third brake light or a fuse.

If the truck does have a brake switch wire you can use, then it will only have power when you step on the brake pedal. Use a circuit tester such as # PTW2993 to find that wire and that is the one the brake controller red wire should be connected to.

If it was working but now it isn't then the likely problem is a blown stop light or CHMSL fuse. I have also included some links on testing and troubleshooting brake controllers for you.

expert reply by: Michael H