Troubleshooting Brake Controller that Only Works When Headlights On and Applies Brakes Gas Pedal

Updated 07/09/2015 | Published 07/08/2015

Products Featured in This Question

Tekonsha Plug-In Wiring Adapter for Electric Brake Controllers - GM

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$21.73

Hook Probe Circuit Tester

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$12.94

Question:

I have installed a P3 controller in a 2001 Suburban 2500. The controller will not work without turning the lights on. Then, when the lights are on, the brakes start to be applied when the gas pedal is pushed. What would cause this?

asked by: Gordie F

Expert Reply:

That is quite the bizarre problem you are having with your brake controller. The problem has to be how the controller is wired to your 2001 Chevy Suburban.

If you used a quick install harness like the # 3025-P my first reaction would be that the pin out of the connector is wrong, or you accidentally used a # 3015-P which uses the same connector but has a different pin out.

I attached a picture of what the pin out should look like. You can test the pins of the port on your vehicle with a circuit tester like part # PTW2993 to verify the circuits of the port.

The red wire of the harness should go to a port with 12 volts only when brakes are applied.
The black wire should see 12 volts all the time.
White wire is ground.
Blue wire is the brake output that carries brake signal to your brakes.