WARNING: This page is about a different car, the 2005 GMC Sierra and 2005 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Cruise Control Schematic (4.3L)
Courtesy of GENERAL MOTORS CORP.
Fig 2: Cruise Control Schematic (4.8, 5.3, 6.0 & 8.1L)