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

Low Speed GMLAN


Object Number: 1860740  Size: FS
Master Electrical Component List
Data Link Communications Description and Operation
Control Module References
High Speed GMLAN
B+ BUS 1 of 2
AMP, BCM, CHMSL/DIMR, HVAC/RFA, and RDO Fuses
AMP, BCM, CHMSL/DIMR, HVAC/RFA, and RDO Fuses
G201
G203 and G205
Figure 2:

High Speed GMLAN


Object Number: 1860741  Size: FS
Master Electrical Component List
Data Link Communications Description and Operation
Control Module References
Low Speed GMLAN