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

Vehicle Communication Interface Module (VCIM) Power and Ground, Inside Rearview Mirror


Object Number: 1424554  Size: FS
Master Electrical Component List
OnStar Description and Operation
Control Module References
Vehicle Interface Unit (VIU), Data Link Connector (DLC)
Horn, Dome, Main, Amp, Onstar Fuses
Junction Block - Instrument Panel Right
SP201 and G201
Figure 2:

Vehicle Interface Unit (VIU), Data Link Connector (DLC)


Object Number: 1426729  Size: FS
Master Electrical Component List
OnStar Description and Operation
Control Module References
Vehicle Interface Unit (VIU)
Vehicle Communication Interface Module (VCIM) Power and Ground, Inside Rearview Mirror
SIR Caution for Zoning
Ignition Switch (1 of 2)
Ignition Switch (2 of 2)
Ignition Switch (2 of 2)
Figure 3:

Vehicle Interface Unit (VIU)


Object Number: 1426731  Size: FS
Master Electrical Component List
OnStar Description and Operation
Control Module References
Vehicle Interface Unit (VIU), Data Link Connector (DLC)
SIR Caution for Zoning