How to Identify the Correct Brake Switch Wire for a Brake Controller on a 2004 Toyota Highlander

Question:

Planning to install Tekonsha P3 brake controller. There are four different color wires going into the brake switch: yellow and black heavier gauge, purple and pink lighter gauge. Which one would I use to connect to the controller? thanks

asked by: Kevin W

Expert Reply:

Unfortunately, Toyota does not use the same color wire for the brake light switch on their vehicles. The best way to determine which wire is the correct wire is to use a circuit tester like part # PTW2993 and test for the wire that only gets hot when the brake pedal is pressed.

I have attached a video of our technician testing for the correct brake switch wire for you to reference. Begin at the 6 minute and 25 second mark. The vehicle in the video is different than yours, but this should give you an idea how to test for the wire.

expert reply by: John H