Difficulty Locating Cold Side of Brake Switch Wire on 2004 Toyota Highlander

Updated 10/31/2017 | Published 10/30/2017

Question:

2004 highlander V6 My stoplight switch has two 16 gage wires one black one yellow. It also has two thinner wires one pink one purple. the purple, pink, and black all are hot. the yellow doe not go hot when depressing the pedal. I thought the yellow one was the cold side, but the article you have stated that when the brake pedal is depressed the cold side goes hot. I am totally confused as to what wire I connect the red wire to. Thanks

asked by: Mike

Expert Reply:

When locating the cold side of the brake switch wire on your 2004 Toyota Highlander, you will need to find the wire that only receives power with the brake pedal depressed and not during any other function. You can use a circuit tester like # PTW2993 to test each of the wires you mentioned in your question. I recommend starting by testing the black wire at the brake switch above the pedal.

The brake switch circuit is typically found near the brake pedal in the vehicle. If you are unable to find the correct wire, you can also try to find the wiring that runs to a third brake light and use it as the stop light circuit for the brake controller. Sometimes you can find the circuit at the fuse box as well as the CHMSL circuit.

You still need to be sure and not use a circuit that also carries a turn signal or other circuit for the controller.

expert reply by: Chris R