2004 Chevrolet Silverado 1500 Pickup Owner's Manual - Page 171

Cruise Control 9(Off): This position turns the system off. {CAUTION: Cruise control can be dangerous where you can not drive safely at a steady speed. So, do not use your cruise control on winding roads or in heavy traffic. Cruise control can be dangerous on slippery roads. On such roads, fast changes in tire traction can cause needless wheel spinning, and you could lose control. Do not use cruise control on slippery roads. R(On): This position activates the system. + (Resume/Accelerate): Push the lever to this symbol to make the vehicle accelerate or resume to a previously set speed. T(Set): Press this button to set the speed. With cruise control, you can maintain a speed of about 25 mph (40 km/h) or more without keeping your foot on the accelerator. This can really help on long trips. Cruise control does not work at speeds below about 25 mph (40 km/h). If you apply your brakes, the cruise control will shut off. 3-11