GMC 1999 Jimmy Owner's Manual page 157

With the automatic setting, the air conditioning
compressor automatically cycles when needed to cool
the air. In cold weather, when the system senses the need
for heat, the airflow will be directed out the floor
outlets. As the interior temperature approaches a desired
setting, the blower speed will decrease. To maintain
interior comfort, the airflow will adjust between the
instrument panel air outlets and floor outlets. On bright
sunny days in cool weather, the airflow may come out of
the air conditioning and floor outlets (bi
maintain comfort and prevent stuffiness.
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 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 your vehicle is sitting out on a warm day and you
have the fan set on AUTO, the air will first flow out of
the floor air outlets for a few seconds. That is normal.
This is to expel hot air from the air outlets. As the air is
cooled, the airflow will move through the air
conditioning outlets.
Be careful not to put anything over the solar sensor
located around the center of the instrument panel.
This sensor is used by the automatic system to
regulate temperature.
Mode Knob
The right knob on the control panel allows you to
choose the direction of air delivery.
You can choose to set the climate control system
-
level mode) to
operations yourself, or let the system work for you by
placing the system in AUTO mode. See "Mode
Knob
through the instrument panel outlets and a small amount
through the floor outlets.
floor outlets as well as the instrument panel outlets.
warmed air through the heater floor outlets and some air
through the windshield defroster outlets.
-
Manual Operation
-
Automatic Operation" earlier in this section.
PANEL: This setting directs most of the air
-
BI LEVEL: Air is delivered through the heater
HEATER: This setting directs most of the
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