Cadillac 1998 Seville Owner's Manual page 155

If your vehicle is sitting out on a hot day and you have it
set on AUTO, the air will first
flow
out the
floor
outlets
for a few seconds. This is normal. This is to remove hot
air from the air outlets. As the air is cooled, the airflow
will move through the air conditioning outlets.
To avoid blowing cold air in cold weather, the system
will start at reduced fan speeds until warm air is
available. The length of reduction depends on the
outside air temperature, engine coolant temperature
or the time since the engine was last started. As the
coolant warms up, the blower 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. If you select defrost mode or a
manual fan speed, this function will be skipped.
If you leave your vehicle, the system will remember
the control setting the next time you start your engine,
except for recirculation and defrost. Each ignition
cycle cancels recirculation. Defrost will change to
automatic operation when the ignition is shut off and
then turned back on.
Electronic Solar Sensor Electronic Solar Sensor
The sensor monitors the sun's solar radiation and is
located near the end of the instrument panel near
the windshield.
The climate control panel uses this information to
automatically make the necessary temperature and
airflow adjustments to maintain your comfort. The
climate control system may supply cooler air to one side
of your vehicle, if that side is facing the sun. Be careful
not to put anything over the sensor on top of the dash.
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