How to Test to Find Brake Light Switch Signal Wire on 2000 Suzuki Grand Vitara

Question:

i have wired brake controllers to brake light switch with no problems, but this vehicle has a different setup. i can not find the answer in the susuki schematics. i have the hot wire going into the sensor and two wires with milliamps coming out. sorry, this is a susuki gran vitara, 2000, 4 door, 4 wheel drive. i have spoken with the people at cequent group and they insist this is the same as a brake light switch. i need help please. i am told the controller will work on milliamps but i cannot verify this info. i apologize i dont know how to give you a picture.

asked by: Bill

Expert Reply:

Some vehicles will have multiple wires leading to/from their brake light switch and that can make it tough to find the correct one for connection to the red input trigger wire of a brake controller like the Prodigy P2 # 90885.

The wire you want to identify through testing (with a circuit tester like # PTW2993) is the one wire that goes hot ONLY when the pedal is pressed. This is the wire that connects to the cold side of the brake light switch. Other wires at the switch may carry a 12V signal but the one you need to wire a brake controller will be the one that goes hot ONLY when the pedal is pressed and at no other time.

Another option for accessing that brake light switch signal is the 3rd brake light or CHMSL (center high-mount stop light). You will need to splice into that circuit and route the wire back to the controller for connection to the red input wire on the controller.

Please refer to the linked article for more on brake controller installation.

expert reply by: Adam R