Here are the notes I used to connect mine:
"Match the colors of each wire and crimp them together with the crimp caps. Do this for all the wires EXCEPT the Red, Yellow, and Blue wires. The constant and switched power wires are flipped, so you will need to connect the Red wire of the Scosche harness to the Yellow wire of the aftermarket one and the Yellow wire of the Scosche harness to the Red wire of the aftermarket harness. The Blue antenna wire on the Scosche unit is actually the remote wire. Attach the Blue-White wire from the aftermarket harness to the Blue wire on the Scosche harness."


In any event you must have power on both the red and the yellow and ground on the black for it to turn on.