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

Ignition I Voltage and 12-Volt Reference


Object Number: 1916217  Size: FS
Master Electrical Component List
Power Mode Description and Operation
Control Module References
Ignition II/III Voltage
Figure 2:

Ignition II/III Voltage


Object Number: 1916242  Size: FS
Master Electrical Component List
Power Mode Description and Operation
Control Module References
Ignition III Voltage and Accessory Voltage
Ignition I Voltage and 12-Volt Reference
Figure 3:

Ignition III Voltage and Accessory Voltage


Object Number: 1916245  Size: FS
Master Electrical Component List
Power Mode Description and Operation
Control Module References
Serial Data Communication Enable
Ignition II/III Voltage