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

Module Power, Ground, and Serial Data


Object Number: 1704032  Size: FS
Master Electrical Component List
OnStar Description and Operation
Control Module References
Communication Signals and Control
B+ Bus - 1 of 3
AMP, ELEC RUN BOARD, ESC/ALC EXH, EXP/BRK MDL, INFO, and TREC Fuses
AMP, ELEC RUN BOARD, ESC/ALC EXH, EXP/BRK MDL, INFO, and TREC Fuses
G301
High Speed Bus - 1 of 2
High Speed Bus - 1 of 2
Low Speed Bus - SP200 - 1 of 3
Figure 2:

Communication Signals and Control


Object Number: 1789486  Size: FS
Master Electrical Component List
OnStar Description and Operation
Control Module References
Module Power, Ground, and Serial Data
G200 - 1 of 2