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

Radio Power, Grounding, Data Bus, VSS Input, and Illumination


Object Number: 1450284  Size: FS
ABS, Blower, Stop-Haz, and IGN B Fuses, and Igntion Switch
Lighting and Battery Fuses
Interior Dimming Schematics
Master Electrical Component List
Radio/Audio System Description and Operation
Radio Speaker Circuits
G200
Data Link Connector (DLC) Schematics
Figure 2:

Radio Speaker Circuits


Object Number: 655346  Size: FS
Master Electrical Component List
Radio/Audio System Description and Operation
Radio Power, Ground, Data Bus, VSS Input and Illumination