Chevrolet avalanche 2002 用户手册

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 outside air temperature,
engine coolant temperature or the time since the engine
was last started. As the coolant warms up, the fan speed
will gradually increase and air will flow from the heater
outlets, with some airflow to the windshield to prevent
fogging under most normal conditions.

Be careful not to put anything over the solar sensor
located near the center of the instrument panel. 
This sensor is used by the automatic system to 
regulate temperature.

On hot days, open the windows long enough to let hot
air inside escape. This reduces the time it takes for your
vehicle to cool down. Then keep your windows closed
for the air conditioner to work its best.

The A/C button, below the mode knob, allows the air
coming into your vehicle to be cooled. This setting is
useful for normal cooling on hot days.

Using A/C with the recirculation setting active allows
the air inside your vehicle to be recirculated. This
setting helps to maximize your air conditioner’s
performance and your vehicle’s fuel economy. This
setting also cools air the fastest and can be used to keep
unwanted odors and/or dust from entering the vehicle.
When using the air conditioner, turn off the recirculation
setting and use the outside air setting after the vehicle
reaches a comfortable interior temperature. When the
right knob on the control panel is between floor and
defrost, the recirculation feature will not function to
reduce window fogging.