GMC G Service Manual page 1277

CHASSIS ELECTRICAL
SUBJECT
Description.................................................................................................................................................................8B- 1
Diagnosis of Headlamps.......................................................................................................................................... 8B- 2
Diagnosis of Front Parking Lamps.........................................................................................................................8B- 3
Diagnosis of Front Side Marker Lamps..................................................................................................................8B- 3
Diagnosis of Rear Side Marker Lamps...................................................................................................................8B- 4
Diagnosis of Running, Park and License Lamps.................................................................................................. 8B- 4
Diagnosis of the Turn Signal and Hazard Systems.............................................................................................. 8B- 5
Diagnosis of the Stoplamp System.........................................................................................................................8B- 6
Diagnosis of the Backup Lamp System.................................................................................................................8B- 6
Front Lighting Systems............................................................................................................................................ 8B- 7
Headlamp System.................................................................................................................................................. 8B- 7
Front Parking Lamps System.............................................................................................................................. 8B- 7
Front Side Marker Lamp System..........................................................................................................................8B- 7
Headlamp Unit Replacement.................................................................................................................................8B-14
Headlamp Adjustment........................................................................................................................................... 8B-14
Lamp Switch Replacement....................................................................................................................................8B-15
Dimmer Switch Replacement................................................................................................................................8B-16
Front Parking Lamp Replacement........................................................................................................................8B-17
Front Side Marker Lamp Replacement................................................................................................................8B-17
Rear Lighting Systems............................................................................................................................................. 8B-19
Rear Running Lamps and Marker Lamps........................................................................................................... 8B-19
Rear Park Lamps................................................................................................................................................... 8B-19
Rear Turn, Stop and Hazard Systems.................................................................................................................8B-19
Backup Lamp System........................................................................................................................................... 8B-19
Rear Lamp Harness Layouts................................................................................................................................8B-21
Trailer Wiring . . ........................................................................................................................................................8B-22
Rear Lamp Bulb Replacement.............................................................................................................................. 8B-28
Rear Lamp Housing and Seal Replacement....................................................................................................... 8B-28
License Plate Lamp Replacement........................................................................................................................8B-29
Rear Marker Lamp Bulb Replacement........................................ ........................................................................ 8B-32
Backup Switch Replacement................................................................................................................................8B-33
Fuses/Circuit Breakers Specifications....................................................................................................................8B-35
R/V Model Fuses.................................................................................................................................................... 8B-35
P-Model Fuses....................................................................................................................................................... 8B-36
G-Model Fuses....................................................................................................................................................... 8B-37
Circuit Breakers..................................................................................................................................................... 8B-37
Lamp Specifications................................................................................................................................................. 8B-38
Special Tools.............................................................................................................................................................8B-39
This Section covers the front and rear lighting systems
and associated wiring, lamps and switches. For problems
within a particular lighting system, refer to the Diagnosis
SECTION 8B
CONTENTS
DESCRIPTION
charts at the front of the section. For On-Vehicle Service of
system components, refer to the service procedures under
the appropriate lighting system.
8B-1
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