For some 2007 - 2013 CTS and CTS-V, extra steps may be necessary to make the unit working.
If the A/C is not working properly, or the unit cannot power on or power off, you may have to get an unused wire (usually a green wire) from the factory A/C harness, and insert the pin of the wire into the position indicated by the red circle in the following picture.
If the sound is not working, first make sure you have the yellowish connector branched off the main harness connected to the back of the unit. If that is not the issue, then please contact us for a proper MCU software (different for with and without BOSE amp).