How to Determine Stop Light Switch for Brake Controller Install on 2018 Toyota Highlander

Question:

On a 2018 Toyota Highlander, what wire on the brake pedal connector do I splice the brake light signal into for the activation of the trailer breaks?

asked by: Ben S

Expert Reply:

When installing a brake controller, the only way to determine the cold side of the stop light switch on any vehicle, including your 2018 Toyota Highlander, is to use a circuit tester such as the very handy Cordless Circuit Tester # PTW2979 and find the wire that only has voltage when you press the brake pedal.

If you take a look at the linked video we did installing the Tekonsha Prodigy P3 Trailer Brake Controller # 90195 on a 2018 Toyota Highlander, if you go to about the 19:20 mark you can see it was a green wire, but yours could be different so you'll need to test it with a circuit tester.

expert reply by: Kyle S