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

Radio


Object Number: 817346  Size: LF
(1)Radio
Figure 2:

Overhead Console w/ C69


Object Number: 817533  Size: LF
(1)HVAC Control Module -- Auxiliary
(2)Rear Seat Audio (RSA) Control
Figure 3:

Overhead Console w/ U32


Object Number: 817618  Size: LF
(1)Rear Video/Audio HVAC Control Module
(2)Video Display Screen
Figure 4:

Overhead Console Controls w/ U32


Object Number: 851859  Size: LF
(1)Rear Video/Audio/HVAC Module