Chevrolet 2002 TrailBlazer Owner's Manual page 176

Mode Buttons
(Recirculation): Press this button to limit the
amount of outside air entering your vehicle. This is
helpful when you are trying to limit odors entering your
vehicle and for maximum air conditioning performance
in hot weather. Recirculation cannot be used in floor,
blend or defrost modes. An indicator on the button will
light up, flash three times and turn off when
recirculation is selected in these modes.
While in the recirculation mode the windows may fog
when the weather is cold and damp. To clear the fog,
select either the blend or defrost mode and increase the
fan speed.
(Air Conditioning): Press this button to turn the
air conditioning compressor on and off. The system will
cool and dehumidify the air inside the vehicle when the
air conditioning compressor is engaged
3-4
Automatic Dual Zone Comfort Control
System (Option)
With this system, you can select different comfort
control settings for the driver and passengers.