WARNING: This page is about a different car, the 2003 Pontiac Montana, 2003 Oldsmobile Silhouette, and 2003 Chevrolet Venture. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Body Control System Schematic (Ignition Input, Door Locks, & Exterior Lamps Output)
Courtesy of GENERAL MOTORS CORP.
Fig 2: Body Control System Schematic (Interior Lights On Request & Horn Control)