How to Find Stoplight Circuit in a 1995 GMC Suburban to Install Brake Controller

Updated 12/08/2014 | Published 12/07/2014

Products Featured in This Question

Draw-Tite Activator IV Trailer Brake Controller - Up to 4 Axles - Time Delayed

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$103.31

Hook Probe Circuit Tester

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$12.27

Question:

which wire or color wire is the cold side of the switch which I need to run myred wire to

asked by: Bob

Expert Reply:

In order to find the correct stoplight circuit wire to use to install a brake controller in your 1995 GMC Suburban you will need to use a circuit tester like part # PTW2993 to test the wires coming out of the brake pedal's stoplight switch until you find a wire that only sees voltage when the brakes are applied and none when released.

Since wire colors can vary this is the most reliable method to use to find the correct wire.

I attached an FAQ on hardwiring brake controllers in vehicles for you to check out as well.

expert reply by: Jameson C