Chevrolet 2000 Impala Owner's Manual page 148

Mode Knob
The knob on the right side of the control panel has
several settings to control the direction of airflow:
UPPER: This setting directs air through the
instrument panel outlets.
-
BI LEV: This setting directs air two ways.
Half of the air is directed through the instrument panel
outlets. Most of the remaining air is directed through the
floor vents and a little to the windshield defroster and
side window outlets.
LOWER: This setting sends most of the air
through the ducts near the floor. The remaining air
comes out of the defroster and side window outlets.
DEFOG: This setting sends half of the air to
the floor ducts and half to the defroster and side window
outlets. The air conditioning compressor will run
automatically in this setting unless the outside
temperature is below 40 _ F (4 _ C). Air inlet will also be
automatically set to outside air. The RECIRCULATION
button will not be selectable in this mode.
DEFROST: This setting directs most of the air
through the defroster and side window vents. Some of
the air also goes to the floor ducts. The air conditioning
compressor will run automatically in this setting unless
the outside temperature is below 40 _ F (4 _ C).
The air inlet will also be automatically set to outside air.
The RECIRCULATION button will not be selectable
in this mode.
OUTSIDE AIR: Press this button to force the
system to use outside air. This button is usable in all of
the mode settings. An indicator on the button will light
up when this button is selected.
RECIRCULATION: Press this button to limit
the amount of fresh air entering your vehicle. This is
helpful when you are trying to limit odors entering your
vehicle. This button is usable in UPPER, LOWER and
-
BI LEVEL modes. An indictor on the button will light
up when this button is selected.
A/C: Press this button to turn the air conditioning
on and off. The system will cool and dehumidify the air
inside the vehicle when the A/C light is on.
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