Wiring a Brake Controller to a 2015 Mercedes Benz Sprinter with Brake Controller Harness

Question:

Found the green connector. which color wire goes for what?

asked by: Frank

Expert Reply:

On a brake controller like the # 90885 the black wire is the 12 volt power wire, the white wire is the ground wire, the blue wire is the brake output, and the red wire is the stoplight switch.

You would need to test the green harness you have found to determine what the functions of the pins on it are. The one with voltage all of the time would be for the black wire, the one with voltage when the brakes are applied is for the red wire.

Ground the tester to the constant 12-volt power wire, then probe the remaining two wires. The wire that lights the tester will be the ground, the other will be the brake output circuit.

expert reply by: Jameson C