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

Low Speed LAN


Object Number: 1942792  Size: FS
Master Electrical Component List
Data Link Communications Description and Operation
Control Module References
High Speed LAN
Figure 2:

High Speed LAN


Object Number: 1942814  Size: FS
Master Electrical Component List
Data Link Communications Description and Operation
Control Module References
Low Speed LAN