There's only three wires, supply power, ground, and signal which is the one you are looking for, I guess. If you don't have access to a wiring diagram, did you visit a dealer and ask as they will give it to you, use a voltmeter and touch any two wires with the sensor unplugged and the ignition on, when you find two wires that give you +5-6V DC, you have found the supply and the ground. The other is the signal. Usually the power is pink with black stripe and the ground is black.