2008 GMC Acadia Owner's Manual - Page 175

Air Conditioning #(Air Conditioning): Press this button to turn the air conditioning (A/C) compressor on and off. When air conditioning is selected, an indicator light comes on to show that the air conditioning has been activated. The air conditioning compressor does not work when outside temperatures fall below 40°F (4°C). Pressing this button when the outside temperature is too cool makes the air conditioning indicator flash three times and turn off to let you know the air conditioning mode is not available. If the air conditioning is on and the outside temperature drops below a temperature which is too cool for air conditioning to be effective, the air conditioning light turns off to show that the air conditioning mode has been canceled. On hot days, open the windows long enough to let hot inside air escape. This helps to reduce the time it takes for the vehicle to cool down. It also helps the system to operate more efficiently. The air conditioning system removes moisture from the air, so a small amount of water may drip underneath your vehicle while idling or after turning off the engine. This is normal. Sensors The solar sensor, located in the defrost grille in the middle of the instrument panel, monitors the solar radiation. Do not cover the solar sensor or the system will not work properly. 3-33