GM Service Manual Online
For 1990-2009 cars only
  1. Slide the turn signal lever cruise switch to the ON position.
  2. Check the low speed inhibit: Drive vehicle at 30-35 Km/h, (18-22 mph). Push SET button and release. Cruise control must not engage.
  3. Check SET speed: Drive vehicle at a steady speed of 90 Km/h, (55 mph). Push SET button completely and release. Cruise control should engage smoothly at 90 Km/h, (55mph).
  4. Check brake release: Depress brake pedal 15-20  mm, (9/16-13/16 in). The cruise control must release allowing the vehicle speed to drop. The system must not re-engage when the brake is released.
  5. Check RESUME feature: With the vehicle speed at appproximately 70 Km/h, (42 mph), slide the cruise switch momentarily (less than 1 second) to the R/A position. The vehicle should accelerate smoothly to approximately 73 Km/h, (45 mph) automatically.
  6. Check COAST feature: Accelerate vehicle to approximately 90 Km/h, (55 mph). Depress the SET/COAST button and hold. Allow the vehicle speed to drop to 80 Km/h, ( 50 mph) and release button. Cruise control should hold vehicle speed at 80 Km/h, ( 50 mph).
  7. Check ACCELERATOR feature: Slide the cruise switch to the R/A position and hold. The vehicle speed should begin to increase. Allow the speed to increase to 90 Km/h, (55 mph) and release switch. The cruise control should hold the vehicle speed at 90 Km/h, (55 mph).
  8. Check OFF switch: Turn the cruise control switch to the OFF position. This must disengage the cruise control system.