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

Vehicle Communication Interface Module (VCIM) - Left


Object Number: 2151417  Size: FS
Master Electrical Component List
OnStar Description and Operation
Control Module References
Vehicle Communication and Interface Module (VCIM) - Right
B+ Bus 2 of 2
Fuse Block - Underhood F28, F10, F22, F2, F1, and F36 Fuses
Power, Ground , Class 2, and GM Low Speed Serial Data (CAN A)
G201 and G202
G201 and G202
Figure 2:

Vehicle Communication Interface Module (VCIM) - Right


Object Number: 2151419  Size: FS
Master Electrical Component List
OnStar Description and Operation
Control Module References
Vehicle Communication and Interface Module (VCIM) - Left
B+ Bus 2 of 2
Fuse Block - Underhood F28, F10, F22, F2, F1, and F36 Fuses
Power Moding Schematics
Power, Ground, DLC, Indicators, Sensors, and References
G201 and G202