Location of 12 Volt Power Wire on 7-Way and the 3rd Brake Light Circuit of a 2005 GMC Sierra

Updated 05/11/2018 | Published 05/09/2018

Question:

Where do i locate the 12 volt feed wire from trailer harness and 3rd brake light wire color from trailer harness i believe its light blue. 2005 gmc sierra. Trying to wire in my canopy.

asked by: Harris R

Expert Reply:

The third brake light wire is not actually part of the trailer wiring, but it should be near it. Look behind your factory 7-way for a light blue wire. It's often in the same wire loom as the 7-way's wiring so you may need to peel back some of the plastic loom. Use a circuit tester like part # PTW2993 to test for function because the color could be different.

The 12-volt circuit is on the trailer connector. It's the wire going into the pin at the 1:00 position on the outside of your 7-way so on the backside it's in the 11:00 position. You can use the circuit tester here too just to be sure but this should be easier to identify.

expert reply by: Charles S