Finding Circuit to Run Red Wire of Brake Controller to for 2004 Lexus RX330

Question:

I’ve converted my 4-way to a 7-way, and now looking to install a Tow Pro Elite brake controller. Everything is pretty straightforward except for the red wire connection. I understand that it needs to connect to a wire that’s hot when the brake is depressed and cold when it isn’t. I’m Having no luck finding an appropriate wire, though. I’ve located the brake switch, which has 4 wires running to it, but I don’t know where to go from there. I’ve thought above using a fuse add-a-circuit, but all the brake-related fuses are associated with other things, too. I’ve been trying to figure this out for a couple days now with no luck! Any advice you can provide would be hugely appreciated!

asked by: Rob W

Expert Reply:

You've done the hard part which is finding the wires on the brake pedal switch so now all you have to do is use a circuit tester like part # PTW2993 to test them all till you find one that has voltage only when the brakes are applied. That will be what you run the red wire of the Tow Pro Elite part # RED44FR to and you'd be set.

expert reply by: Jameson C