I have a D3 and I am trying to get the factory DVD player to work. I bought the Metra 70-5520AV wiring harness. It has a black wire, blue/white wire, and red/white RCA outs. I'm not sure where to connect these wires. I assume that the black wire goes to ground, the red/white RCAs go to the audio input on the D3, but where does the blue/white go? Any help would be appreciated.