Buick 1993 LeSabre Owner's Manual page 128

Bi-Level
This setting is designed for
use on
sunny days when the
air is only moderately warm or
cool.
On days like these,
the sun may adequately warm your upper body, but your
lower body may not be warm enough.
The Bi-level setting directs outside air into your vehicle
in two ways. Cool air is directed toward your upper
body through the instrument panel outlets, while slightly
warmed air is directed through the heater outlet at your
feet.
The air conditioner compressor operates in all Air
Conditioning positions and the Defrost position when
the outside temperature is above 48 OF (9OC).
When you don't need to cool the outside air, use the
VENT, HEAT, or DEFROST settings. Adjust the
temperature control for comfort. You'll get better fuel
economy (gas mileage) if you're not cooling the outside
air. When you cool the air, your engine runs a
refrigeration compressor, and it has to work harder.
Vent
For mild outside temperature, when little heating or
cooling is needed, use the VENT setting. Air will flow
through the instrument panel outlets. Use the air outlets
to turn on, adjust and turn off the air flow. Adjust the
temperature lever to the desired temperature.
Heater
When outside temperatures are cold, pressing the HTR
setting and adjusting the temperature lever will send
warm air through the floor outlets, and some through the
defroster vents.
Def
The Defrost setting directs most of the air flow toward
the windshield. Use defrost when you want to remove
fog or ice from the windshield. When it's 48 OF (9
"C) or
warmer, you'll get cooled air.
Defog
Air entering the car will be evenly split between the
floor outlets and the outlets near the windshield. You
can control the temperature of the air and the fan speed
to clear the foggy windows.
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