2004 Chevrolet Silverado 1500 Pickup Owner's Manual - Page 187

If the driver and passenger's temperature settings are not the same, the opposite side temperature setting will be displayed for an additional five seconds. To make the passenger's temperature the same as the driver's press and hold the AUTO button for about four seconds. When AUTO is selected, the air conditioning operation and air inlet will be automatically controlled. The air conditioning compressor will run when the outside temperature is over about 40°F (4°C). The air inlet will normally be set to outside air. If it's hot outside, the air inlet may automatically switch to recirculate inside air to help quickly cool down your vehicle. The light on the button will illuminate in recirculation. 2. Set the driver's and passenger's temperature. To find your comfort setting, start with a 74°F (23°C) temperature setting and allow about 20 minutes for the system to regulate. Turn the driver's or passenger's side temperature knob to adjust the temperature setting as necessary. If you choose the temperature setting of 60°F (15°C) the system will remain at the maximum cooling setting. If you choose the temperature setting of 90°F (32°C) the system will remain at the maximum heat setting. Choosing either maximum setting will not cause the vehicle to heat or cool any faster. Be careful not to cover the sensor located on the top of the instrument panel near the windshield. This sensor regulates air temperature based on sun load, and also turns on your headlamps. To avoid blowing cold air in cold weather, the system will delay turning on the fan until warm air is available. The length of delay depends on the engine coolant temperature. Pressing the fan switch will override this delay and change the fan to a selected speed. 3-27