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

Power, Ground, Button Assembly, and Microphone


Object Number: 788026  Size: FS
Master Electrical Component List
OnStar Description and Operation
VCU/VIU Communications
Underhood Fuse Block Fuse V6 and Fuse Block Fuses 17, 28, 29, 33, and34
Underhood Fuse Block Fuse V6 and Fuse Block Fuses 17, 28, 29, 33, and34
G201
DLC Pins 2, 4, 5, 16
Figure 2:

VCU/VIU Communications


Object Number: 788029  Size: FS
Master Electrical Component List
OnStar Description and Operation
Power, Ground, OnStar Button Assembly, and Microphone