This system has been seriously complicated with computer controls and digital signals. You are going to have to take some voltage readings to see if there is a circuit that can be used.
Look at the center tail lamp assembly. It should have three black wires going to it. Measure the voltages on those wires with a digital voltmeter when the back-up lamps are on. If you find twelve volts on two of those wires, you should be able to use either one of them.
Monday, May 22nd, 2017 AT 9:14 PM