How To Find The Cold Side Of The Stoplight Switch On A 2004 Lexus RX 330

Question:

Need install brake control on 04 Lexus rx330. Need info on locating cold side stoplight switch…I.e. location of wire in harness so as not to have to disassemble dash.

asked by: David

Expert Reply:

The stoplight switch on your 2004 Lexus RX 330 should be located right near the tip of your right foot, near the brake pedal, and can be quite challenging to get to.

When it comes to finding what is the cold side and hot side, you are going to need to first test the wires connected with a circuit tester # PTW2993 and check the wires for function. You will need to find the wire that shows power only when the brake pedal is pressed.

This wire will be the wire that you use to connect to a brake controller, like the Tekonsha PowerTrac Electronic Brake Controller # 39523 with the Replacement Brake Control Plug-In Harness for Tekonsha and Draw-Tite Brake Controller # 20127.

If you are not able to locate the cold side of your stoplight switch, then you can use the Roadmaster Stop Light Switch Kit # RM-751490 and use that instead.