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

Selectable Transfer Case Wiring


Object Number: 583129  Size: MF
(1)Engine Harness
(2)Connector C120
(3)Vehicle Speed Sensor to Engine Harness
(4)Shift Motor Power
(5)Vehicle Speed Sensor
(6)Encoder Connector
(7)Transfer Case Switch
(8)PNP Switch
Figure 2:

Transfer Case Select Switch


Object Number: 183948  Size: LF
(1)Radio Connector
(2)Rear Wiper Switch
(3)Cargo Lamp Switch
(4)Rear Fan Switch
(5)Electric Shift Transfer Case Switch or Fog Lamp Switch
Figure 3:

C100, C140, C142, P100


Object Number: 634900  Size: MF
(1)Pass Through Grommet P100
(2)Connector C100
(3)Engine Harness
(4)Connector C140
(5)Connector C142
Figure 4:

Front Axle Actuator Wiring


Object Number: 601510  Size: LF
(1)Transfer Case Harness
(2)Starter
(3)Battery Cable
(4)Front Differential
(5)Actuator Motor
(6)Actuator Connector
(7)Frame