Identifying Brake Switch Wiring And Trailer Brake Output Wires For a Brake Controller Installation

Published 10/09/2021

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Question:

What is the difference in a brake switch and the output to trailer brakes?

asked by: Jamey

Expert Reply:

The brake switch is what tells your vehicle that your brake pedal has been pressed and will turn on your brake lights as well as tell the cruise control to disable, and trailer Brake Controller # 90195 to send power to the trailer brakes. This switch generally does not carry a lot of amperage and uses small gauge wiring to send the signals. The switch will have wiring that always has power and wiring that only receives power when the brake pedal is pressed. You can use a Test Light # PTW2993 to identify which wires are activated. The wire that only receives power when the brake pedal is pressed is the one your brake controller receives its signal from.

The output to the trailer brakes is going to be a larger wire that comes off of the brake controller to the 7-way connector on your vehicle. This wire is larger as it will carry the higher amperage power needed to activate the trailer brakes. The amount of power will vary depending on how much braking the controller is set for and how many braking axles the trailer has.

If you need help with an installation on a certain vehicle or are having trouble with a current brake controller please let me know what you have as that will allow for me to better help with your situation.

expert reply by: Bud M