Where is the Brake Switch Wire on a 2014 GMC Savana Van to Install a Brake Controller

Updated 04/14/2025 | Published 08/27/2015

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Question:

Looking for wire to hookup from brake switch.

asked by: Andrew

Expert Reply:

I can tell you were to access the correct brake switch wire to install a brake controller on your 2014 GMC Savana Van. You will need to access the wire behind the BCM (body control module) located behind the dash on the passenger's side of the vehicle.

There should be a brown connector coming out of the back of the BCM. At that connector you should find a light blue/white wire. This is the wire that carriers the dedicated brake light signal. Use a circuit tester such as # PTW2993 to confirm that it only has power when the brake pedal is pressed. I have also included a picture showing the wire.

If you do not already have a brake controller, I recommend the P2 # 90885 because it is easy to set up and use and it is reliable.

expert reply by: Michael H

click to enlarge

Daniel H.

12/21/2024

Would i use the same wire on my 2021 gmc savana? I bought all of the recommended supplies from e-trailer and im having a hard time with my wiring. Im very nervous to cut into wiring at the BCM for fear that it may cause issues with the van. Thanks

Kevin C.

12/23/2024

@DanielH Before splicing into anything you'll want to check for wiring taped up and tucked under the driver side floor mat up towards the firewall. On some models the GM already has a little bundle of wires ran for this to make splicing in your brake controller harness easier. If you find you don't have that bundle you'll need to test the wires leading from the brake pedal to find the one that only has power when the brake pedal is being depressed. I would start with that light blue/white wire since it's likely going to be the correct wire, but there's no confirmation that it is for this model year. If you can't find the correct wire or don't want to splice into the factory wiring you can also just install a stop light switch # RM-751000 and use its output for the connection to the red wire from the brake controller wire harness.

Jeff

4/14/2025

@KevinC Did you figure it out for your 2021 Savana? I'm trying to figure it out right now. The brown connector doesn't seem to have any wires that are hot when pressing the brake pedal. The trailer wiring by the parking brake pedal also does not work.