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

Power, Ground, Serial Data and Horn References


Object Number: 1228271  Size: FS
Master Electrical Component List
Body Control System Description and Operation
Door Locks, Headlamps/DRL, Exterior Lights, Pass Lock References
B+ BUS - Fuse Block Underhood
ACCY/RUN and RUN/START BUS BAR
B+ Bus - Fuse Block - Rear
ACCY/RUN and RUN/START BUS BAR
ACCY/RUN and RUN/START BUS BAR
G103, G104
Data Link Connector (DLC) Schematics
Horn Schematics
Figure 2:

Door Locks, Headlamps/DRL, Exterior Lights and Passlock References


Object Number: 1228422  Size: FS
Master Electrical Component List
Body Control System Description and Operation
Interior Lights, Interior lightsDimming, Brake Warning and Audible Warning References
Power, Ground, Serial Data and Horn References
Power Door Locks
Fog Lights Schematics
Headlamp and Headlamp Dimmer Switch Control
Steering Wheel Controls Schematics
Backup Lamps
Park Lamp Control, Turn Signal Inputs and Hazard Switch
Headlamp Relay Control
Day Time Running Lamp (DRL) Relay Control
Vehicle Theft Deterrent
Figure 3:

Interior Lights, Interior Lights Dimming, Brake Warning and Audible Warning References


Object Number: 1228429  Size: FS
Master Electrical Component List
Body Control System Description and Operation
Door Locks, Headlamps/DRL, Exterior Lights, Pass Lock References
Interior Lights Dimming Schematics
Interior Lights Dimming Schematics
Interior Lights Schematics
Headlamp Relay Control
Wiper/Washer System Schematics
Brake Warning System Schematics
Audible Warnings Schematics
Door Ajar Switches