GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2009 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Power and Signal Distribution 🢒 Wiring Systems and Power Management 🢒 Upfitter Provision Schematics
Figure 1:

X103 - Upfitter Auxiliary Wiring Connector
Object Number: 2076523 Size: FS
Figure 2:

PTO Connectors
Object Number: 2076525 Size: FS