Have done this in my Corvette and just got a new Valentine 1 for the HHR. A company called "invisicord" makes a cable to wire your detector up with via the connector that goes to the auto dimming mirror. For the 16 pin connector on my 2009 SS I needed pin 8 (black wire) and pin 13 (pink wire - +12 volts when ignition is on). Works like a champ if you want to hide those wires.

 

i would like to see pictures with the radar and pin set up..