2010 GMC Sierra 1500 Crew Cab Owner's Manual - Page 248

Driver and Passenger Side Temperature Controls The driver and passenger side temperature buttons are used to adjust the temperature of the air coming through the system on the driver or passenger's side of the vehicle. The temperature can be adjusted even if the system is turned off. This is possible since outside air always flows through the system as the vehicle is moving forward unless it is set to recirculation mode. See "Recirculation" later in this section. Press the + or − buttons to increase or decrease the cabin temperature. The driver side or passenger side temperature display shows the temperature setting decreasing or increasing. The passenger's temperature setting can be set to match the driver's temperature setting by pressing the PASS button and turning off the PASS indicator. When the passenger's temperature setting is set different than the driver's setting, the indicator on the PASS button illuminates and both the driver side and passenger side temperature displays are shown. When in defrost mode the passenger temperature setting cannot be changed. Automatic Operation AUTO (Automatic): When automatic operation is active the system controls the inside temperature, the air delivery, and the fan speed. Use the steps below to place the entire system in automatic mode: 1. Press the AUTO button. When AUTO is selected, the display changes to show the current temperature(s) and AUTO is lit on the display. The current air delivery mode and fan speed are also displayed for about 5 seconds. When AUTO is selected, the air conditioning operation and air inlet are automatically controlled. The air conditioning compressor may run when the outside temperature is above freezing. The air inlet will normally be set to outside air. If it is hot outside, the air inlet may automatically switch to the recirculate mode to help quickly cool down the air inside the vehicle. The light on the button comes on in recirculation. 4-24