For Sale .. AOEM-GM1416A , for adding a aftermarket amp to your factory radio ,fits 2006-2008 HHR ,Cobalt 07-08 Some others. The wiring has been modified so that you can use a 4 channel amp and send the signal back to your factory wiring with no cutting of the factory harness. The original pac module untouched ties into the wires to get the signal, each channel can be amplified but the sound is still going to your original speakers un amplified..
$35 plus shipping