WARNING: This page is about a different car, the 2001 GMC Safari and 2001 Chevrolet Astro. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
For additional circuit identification, see DATA LINK CONNECTORS, GROUND DISTRIBUTION and/or POWER DISTRIBUTION articles in WIRING DIAGRAMS.
Fig 1: Body Control Module Wiring Diagram (Astro & Safari)