Originally Posted by Razorback
Good luck. I'm in the same boat. The wires are NOT where they say on the instruction disc you got. I found the wire to be the white with red stripe WH/R, even though it says it should be the wht/light green stripe WH/LG. (2011 CC sport) AND it was not in C5 for 2009-10 or in C15 for 2011-12. Probed the wires and WH/R was the one that switched on when in reverse. Verified by checking the wire to the reverse lamp in the tail light, same colors WH/R. This should be what your looking for.
The above is for the power wire and is part of the harness (WHT/LG wire from harness splices to WHT/R wire from the brown plug )
The 3 pin connectors go in slots 3,4 and 5 of the WHITE connector on the passenger side of the radio, NOT the existing grey plug. If yours doesnt have one use the one supplied in the kit.