Where to Find Stop Light Circuit for Installing Brake Controller in a 2008 Saturn Vue

Published 11/25/2015

Question:

When installing a Tekonsha P3 brake controller, the instructions direct that the red wire from the controller is connected to the cold side of the brake switch. I am wiring mine up to a 2008 Saturn Vue but both sides of the switch are hot when the brakes are not activated. The purple wire lt blue in the schematic is cold when the brake is depressed. Does this mean that I will have to install a relay to flip the signal cold when not depressed and hot when depressed? Also, is there any way to test the brake controller output without connecting a trailer? I just want to ensure that my installation is correct. Thanks,

asked by: Jeffery K

Expert Reply:

This question comes up more frequently for the Chevy Equinoxes, but the solution is the same for the Saturn Vues.

To get it under the dash you need to access the BCM (body control module). It is located under the dash above where your left knee would be. The module will have several different wire connectors that plug into it.

It could be connector 2, pin 30 or it could be position 11. One thing that seems to be constant on the vehicles affected is that the wire is usually white so you might want to start with those.

The same rules apply for the locations at the BCM: you need the one that only shows power with the brake pedal pressed and not at any other time.

expert reply by: Jameson C