I have a new 8200nex and the required kits from crutchfield. When i use onstar, my 8200 powers down completely while im using the OnStar feature. I did properly cable the AXXESS brown wire to the mute wire on the 8200 so its not supposed to power down. Once done with OnStar, the 8200 powers back up but there is no volume. Then if i shut my car off and open the door to kill the acc delay, then turn the car backon, the 8200 acts like only at 25% volume level, even with the volume cranked up to the max. To reset everything, i have to unplug the main harness which resets the whole unit.

I would take it back to the installer and explain the problem and he will fix it up.