WARNING: This page is about a different car, the 2003 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Diagnosis Procedure - Cruise Control Indicator Always On (Steps 1 To 2)
Courtesy of GENERAL MOTORS CORP.
Fig 2: Diagnosis Procedure - Cruise Control Indicator Always On (Steps 3 To 6)