GM Service Manual Online
For 1990-2009 cars only
Figure 1:

Front of I/P


Object Number: 761603  Size: LF
(1)Vehicle Interface Unit (VIU)
(2)Bracket
(3)Vehicle Communications Unit (VCU)
Figure 2:

Overhead Console


Object Number: 760729  Size: SH
(1)OnStar Button Assembly
(2)OnStar Microphone
(3)Garage Door Opener