GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 Sonoma Pickup - 2WD 🢒 Body and Accessories 🢒 Cellular Communication 🢒 OnStar Schematics
Figure 1:

Cell 154: Vehicle Interface Unit (VIU)
Object Number: 381450 Size: FS
Cell 10: AUX PWR, RDO BATT and HDLP SW Fuses
Cell 10: RDO IGN and STR WHL RDO IGN Fuses
Cell 10: AUX PWR, RDO BATT and HDLP SW Fuses
Cell 10: RDO IGN and STR WHL RDO IGN Fuses
Handling ESD Sensitive Parts Notice
Cell 50: Power, Ground, SDM and VIU
Cell 14: G200, G201 and G207 (2-Door Utility w/ Endgate)
Entertainment Connector End Views
Cell 86: Power and Ground (w/ Trip Computer)
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
SIR Handling Caution
Cellular Communication Components
OnStar Circuit Description
Cell 154: Vehicle Communication Unit (VCU) and Floor Handset
Cell 154: Vehicle Communication Unit (VCU) and Floor Handset
Figure 2:

Cell 154: Vehicle Communication Unit (VCU) and Floor Handset
Object Number: 381453 Size: FS
Cell 154: Vehicle Interface Unit (VIU)
Cellular Communication Components
OnStar Circuit Description
Cell 154: Vehicle Interface Unit (VIU)
Handling ESD Sensitive Parts Notice