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

Except Envoy


Object Number: 562910  Size: FS
Power and Grounding Components
Cigar Lighter/Auxiliary Outlet Circuit Description
Envoy Only
INT BATT Fuse
AUX PWR, RDO BATT and HDLP SW Fuses
Power, Ground, Transfer Case Shift Control Module and Vehicle Interface Unit (VIU)
Amplifier Power and Ground (Chevy/GMC)
G203 and G204 (Utility w/ Automatic A/C)
2000 S/T Headlight Leveling
Figure 2:

Envoy Only


Object Number: 562914  Size: FS
Power and Grounding Components
Cigar Lighter/Auxiliary Outlet Circuit Description
Except Envoy
INT BATT Fuse
AUX PWR, RDO BATT and HDLP SW Fuses
Power, Ground, Transfer Case Shift Control Module and Vehicle Interface Unit (VIU)
G203 and G204 (Utility w/ Automatic A/C)
G205 and G208 (Envoy)
G470 (Envoy)
ALC Suspension Schematics