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

Power and Ground


Object Number: 794614  Size: FS
Master Electrical Component List
OnStar Description and Operation
Keypad Microphone Signals
Serial Data Class 2
G401 (2 of 2)
Battery Feed to the Fuse Block-Rear
Battery Feed to the Fuse Block-Rear
Figure 2:

Keypad Microphone Signals


Object Number: 625377  Size: FS
Master Electrical Component List
OnStar Description and Operation
VIU and VCU Signals
Power and Ground
G402
G402
Figure 3:

VIU and VCU Signals


Object Number: 694103  Size: FS
Master Electrical Component List
OnStar Description and Operation
Keypad Microphone Signals