GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2003 🢒 Express 🢒 Body and Accessories 🢒 Body Control System 🢒 Body Control System Schematics
Figure 1:

Power, Ground, Serial Data and Controlled/Monitored Subsystem References
Object Number: 848096 Size: FS
Master Electrical Component List
Body Control System Description and Operation
Lighting Subsystem References
B+ Bus - Underhood Fuse Block
IGN B Fuse
CRANK, IGN O, TBC ACC, FR WPR, BRKS, and HVAC Fuses
IGN B Fuse
Data Link Schematics
Horns
Retained Accessory Power Schematic
DRV LKS, DOOR LKS, CARGO UNLK Fuses, and DRV UNLK, DOOR LKS, PASS UNLK, CARGO UNLK Relays
DRV LKS, DOOR LKS, CARGO UNLK Fuses, and DRV UNLK, DOOR LKS, PASS UNLK, CARGO UNLK Relays
DRV LKS, DOOR LKS, CARGO UNLK Fuses, and DRV UNLK, DOOR LKS, PASS UNLK, CARGO UNLK Relays
DRV LKS, DOOR LKS, CARGO UNLK Fuses, and DRV UNLK, DOOR LKS, PASS UNLK, CARGO UNLK Relays
Audible Warnings Schematics
Brake Warning Schematic
Door Lock Switches
Theft Deterrent System
Temperature/Pressure/Range Switches, and VSS
Temperature/Pressure/Range Switches and VSS
G303, and G304
Fuse Block - Rear and Access Panel Relays
Fuse Block - Rear and Access Panel Relays
Fuse Block - Rear and Access Panel Relays
Figure 2:

Lighting Subsystem References
Object Number: 848099 Size: FS
Master Electrical Component List
Body Control System Description and Operation
Power, Ground, Serial Data, and Controlled/Monitored Subsystem References
Courtesy Lamps w/o YF7 - 1 of 2
Courtesy Lamps - YF7
Controls and Backlighting - 1 of 3
Driver, Passenger, and Cargo Mini Wedges
Underhood Lamp, Rear Door Ajar Switches, and Vanity Mirrors
Backup Lamps (w/o Cutaway) and Front Park/Turn/Marker Lamps
Inside Rearview Mirror
Headlights
Headlamp and Panel Dimmer Switch, Park Lamp Relay, and FR PRK, LR PRK, RR PRK, TRLR PRK, UPFTR PRK Fuses
Driver, Passenger, and Cargo Mini Wedges
FLASHER, IGN E, and STOP LP Fuses
Headlights
Controls and Backlighting - 1 of 3
Headlamp and Panel Dimmer Switch, Park Lamp Relay, and FR PRK, LR PRK, RR PRK, TRLR PRK, UPFTR PRK Fuses
Controls and Backlighting - 1 of 3