I'm just curious about this. Is it possible to keep the onstar mic for use with a new head unit since I don't use the onstar service itself and I'd rather not hang a mic from my sun visor?
This is exactly what I would like to do also!
I am in the process of installing a new head unit in my 2006 and wondered the same thing. If I could use the Onstar mic built into rear view mirror.
I'm following this. I just got a Kenwood Excelon DDX396 installed in my base 2009 vibe, and now have the cheap mic pinned to the dash. Other than this disappointment, I love the upgrade. I'm getting amazing sound through the stock speakers. I ran a USB cable into the console and now have access to 1000's of songs.