Cadillac 1999 DeVille Owner's Manual page 168

Ventilation System
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Your vehicle's flow through ventilation system supplies
outside air into the vehicle when it is moving. Outside
air will also enter the vehicle when the heater or the air
conditioning fan is running.
The front outlets are located in the center and at each
side of the instrument panel. You can adjust the
direction of airflow by moving the center control levers
or you can stop the airflow by moving the lever located
on each side of the outlets downward.
3-12
The direction of airflow to the rear seats can be adjusted
if you have the optional full console (DeVille Concours
only). Move the fan lever to adjust the blower
speed from low to high. Move the vent lever to direct
the airflow.
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