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

Power, Ground, DLC, and Front Door Speakers


Object Number: 851811  Size: FS
Master Electrical Component List
Radio/Audio System Description and Operation
Radio w/UK6
B+ Bus - Underhood Fuse Block
TBC, TBC 2, TBC 3, TBC 4,RADIO BAT, RR DEF/HTD MIR, FLASHER, and RFA Fuses, and PWR SEAT Circuit Breaker
Data Link Schematics
Cellular Communication Schematics
G303, and G304
Figure 2:

Radio w/UK6


Object Number: 851812  Size: FS
Master Electrical Component List
Radio/Audio System Description and Operation
Radio w/o UK6
Power, Ground, DLC, and Front Door Speakers
Controls and Backlighting - 2 of 3
G303, and G304
Figure 3:

Radio w/o UK6


Object Number: 851813  Size: FS
Master Electrical Component List
Radio/Audio System Description and Operation
Radio w/UK6