WARNING: This page is about a different car, the 2008 Isuzu Ascender, 2008 GMC Envoy, and 2008 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Transfer Case Control Schematic
Courtesy of GENERAL MOTORS CORP.
Fig 2: Power, Ground, Serial Data & Transfer Case Encoder Motor Schematic
Courtesy of GENERAL MOTORS CORP.
Fig 3: Speed Signal, Front Axle Actuator & Indicators Schematic