Trouble Finding Cold Side of Brake Light Switch on 2003 VW Eurovan

Updated 06/29/2018 | Published 06/27/2018

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Question:

Two wires are hot ,12.4 volts, then when brake is depressed, o.o volts. The other two 0.0 volts.

asked by: PERRY G

Expert Reply:

The cold side of the brake light switch will be the wire that only receives power with the brake pedal pressed and no power with any other function. Not only will you want to test the wires with the brake pedal pressed down, but you should also test each of the 4 wires you found with other functions like turn signals or brake lights. The correct wire will only show voltage with the brake pedal pressed.

If you cannot find the appropriate wire above the brake pedal, you may need to tap into a dedicated brake light circuit elsewhere. There should hopefully be a stoplight or CHMSL fuse in the fuse box that you can tap into. You will want to check your copy of the Eurovan's owner's manual for the fuse location.

expert reply by: Chris R