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

Headlamp Switch and Ambient Light Sensor


Object Number: 661617  Size: FS
Master Electrical Component List
Exterior Lighting Systems Description and Operation
Headlamp Dimmer, Park Gear Input, and High Beam Indicator
Underhood Fuse Block, RUN/CRK Fuse and IGN Relay
Underhood Fuse Block and Underhood Maxi-Fuse Block
Underhood Fuse Block- PCM, ABS, HZDT/SG, F/PMP, PK LP Fuses and F/PMP Relay
Underhood Fuse Block and Underhood Maxi-Fuse Block
Underhood Fuse Block- OXY SEN and SBM LCM Fuses
G202 (1 of 4)
G202 (4 of 4)
G202 (1 of 4)
G202 (2 of 4)
Figure 2:

Headlamp Dimmer, Park Gear Input, and High Beam Indicator


Object Number: 661618  Size: FS
Master Electrical Component List
Exterior Lighting Systems Description and Operation
Daytime Running Lamps
Headlamp Switch and Ambient Light Sensor
G202 (4 of 4)
G202 (1 of 4)
Figure 3:

Daytime Running Lamps


Object Number: 661619  Size: FS
Master Electrical Component List
Exterior Lighting Systems Description and Operation
High Beam Headlamps
Headlamp Dimmer, Park Gear Input, and High Beam Indicator
VIU Output Signals
G104 and G106
G104 and G106
G105
G105
Figure 4:

High Beam Headlamps


Object Number: 661621  Size: FS
Master Electrical Component List
Exterior Lighting Systems Description and Operation
Daytime Running Lamps
G104 and G106
G104 and G106