Where to Attach the Brake Controller Red Wire on a 2012 Cadillac SRX

Updated 07/15/2025 | Published 02/01/2012

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Question:

How do you pick up a brake input for a trailer brake control on a 2012 SRX? These vehicle do not have a brake switch. They use a brake pedal position sensor and have led tailamps and brake lights. Have not been able to find a 12 volt brake on input. Thanks for any help you can provide.

asked by: Ted E

Expert Reply:

I spoke with my contact at Tekonsha and Tow Ready and I believe that I can help you locate a place to attach the brake controller red wire on your 2012 Cadillac SRX. The vehicle does have a dedicated stop light circuit located in the BCM (body control module).

The hardest part is going to be locating the BCM, but once you find it, it should be easy. The BCM is located under the left (driver) side of the dash. You will know it is the correct one because there will be 7 connectors plugged into it.

All 7 connectors will be a different color. You need connector X4, the black connector. In connector X4 there should be a white wire in terminal 11. This is the dedicated third brake light wire. Use a circuit tester like # PTW2993 to make sure that is the correct wire. It should only show a signal on the circuit tester when the brake pedal is pressed.

It does sound a little complicated but given enough time and patience, a bright flashlight, and a free afternoon, you should be able to locate the proper wire for your brake controller.

expert reply by: Michael H

7/14/2025

found bcm and black connector / white wire had blue stripe tried getting signal, don't known lf I had a good ground?

Lazer S.

7/15/2025

@Jd A bad ground can definitely cause all kinds of issues, even when testing. That said, I could not find a wiring diagram that mentioned a white wire with a blue stripe, so I don't think that is the correct one. I know it's a pain, but you will need to test each wire while pressing the brake pedal to see which is active when the pedal is pressed. Sorry I can't be more help than that. If you can't get it figured out, let me know. We do have an installer locator and can get you hooked up with one near you if needed.