How Does a Proportional Brake Controller Work

Updated 07/23/2024 | Published 07/19/2024

Question:

My truck, 2018 GMC Canyon with factory wiring for trailers except braking. Can you explain to me how the wiring kit that comes with the controller that sells for 174 works. It looks like will I would have to strip and splice. Kind of crude now days.

asked by: William B

Expert Reply:

Hey William, it looks like you're asking about the Tekonsha Prodigy P3 Trailer Brake Controller # 90195. This is a proportional brake controller, so basically how it works is the brake controller will activate the trailer brakes with the same intensity and at the same time as the tow vehicle.

This brake controller also automatically adjusts the trailer's braking based off of the deceleration of the tow vehicle.

expert reply by: Bryce D

William R.

7/22/2024

I understand how well your controller works. What I want to know is information about wiring the controller to the wiring harness under the dash. Is any information you will provide generic or is it specific to my truck?

Bryce D.

7/22/2024

@WilliamR I gotcha, so unfortunately you're still going to have to hard wire the wires to your truck. No plug is under the dash, but the needed wires are already run. The wiring diagram goes as follows: 1. Black - goes to the positive terminal on your battery; 2. Red - would need to get connected to the stoplight switch; 3. White - goes to a known ground; 4. Blue - goes to the brake output.

William

7/22/2024

@BryceD Ok, 1 and 3 I get. 2 means connect to the cold side of the brake switch which turns hot when the break petal is pressed. 4 is a mystery. Sounds like you mean connect to the 'hot ' side of the brake switch, which is on when the ignition switch is on. Correct?

Bryce D.

7/22/2024

@William Yes, that is correct.