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

HPZ with Manual Transmission


Object Number: 1908537  Size: FS
Master Electrical Component List
Two Speed Rear Axle Shift System Description and Operation (Electric Operated)
Control Module References
HPZ with Automatic Transmission
HP1/HP2
Engine Data Sensors - Low Reference 2 of 2
Ground Distribution Schematics
AXL/4WD, BRK, HYD/AIR BRK, and HTR/AC Fuses/Circuit Breakers
G200, G202, and G203 - 1 of 4
Figure 2:

HPZ with Automatic Transmission


Object Number: 1908532  Size: FS
Master Electrical Component List
Two Speed Rear Axle Shift System Description and Operation (Air Operated)
Control Module References
HPZ with Manual Transmision
Engine Data Sensors - Low Reference 2 of 2
ENG-1 and ENG-4 Fuses - L18/LMM
ENG-1 and ENG-4 Fuses - LF6/LF8
ENG-1 and ENG-4 Fuses - L18/LMM
ENG-1 and ENG-4 Fuses - LF6/LF8
Engine Data Sensors - Low Reference 2 of 2
Ground Distribution Schematics
AXL/4WD, BRK, HYD/AIR BRK, and HTR/AC Fuses/Circuit Breakers
G200, G202, and G203 - 1 of 4
Figure 3:

HP1/HP2


Object Number: 1908534  Size: FS
Master Electrical Component List
Two Speed Rear Axle Shift System Description and Operation (Air Operated)
Control Module References
HPZ with Manual Transmision
Engine Data Sensors - Low Reference 2 of 2
G100 - LF8