I'm lost. I connected the basic wires (red/yellow/black) from the D3 to the 70-7551 wiring harness. The harnesses have 2 pair of RCA for front and rear speakers.

Questions:

1. Am I to connect the D3 RCA to the radion harness?

2. What do I connec the Blue/White (Amp turn on) and Black/White(Amp ground) from the harness to?

3. Also, can I connect the D3 ground (black) to the radio harness ground instead of the vehicle metal body?

Thanks....

yes, rca's from d3 to rca's of harness. the blue/white from d3 to blue/white or blue from metra harness (whichever it has). you dont need to hook up the amp ground from the metra harness. the ground in the harness is fine if it has one