2002 GMC YUKON Owner's Manual

3-5
A/C (Air Conditioning):Press this button to turn
Fan Cont rol

3-6
When both the fan control and mode knobs are in the
AUTO position, the system will then automatically
maintain the desired cabin temperature as selected.
Manual control of functions is also available.
Temperature Knob
The middle knob on the control panel lets you select the
desired air temperature in your vehicle. This knob will
allow you to adjust the interior air temperature
independent of the function knob setting. Move the knob
clockwise toward 82
F (28
C) for warmer air. Move the
knob counterclockwise toward 66
F (19
C) for cooler
air. When the system is set for automatic operation,
sensors will control the fan speed.
Full Hot: If you turn the temperature knob past 82
F
(28
C), the system will go into the ªfull hotº mode. The
system will remain at that maximum heating setting and
the fan will blow at the speed the fan knob is set to. If
the fan is in AUTO, it will run at full speed.
Full Cold: If you turn the temperature knob past 66
F
(19
C), the system will go into the ªfull coldº mode.
The system will remain at that maximum cooling setting
and the fan will blow at the speed the fan knob is set to.
If the fan is in AUTO, it will run at full speed.Mode Knob -- Manual Operation
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
yourself, or let the system work for you by placing the
system in AUTO mode. See ªMode Knob
-- Automatic
Operationº later in this section.
(Vent): This setting directs most of the air through
the instrument panel outlets and a small amount through
the floor outlets.
(Bi-Level): Air is delivered through the floor
outlets as well as the instrument panel outlets.
(Floor): This setting directs most of the warmed
air through the floor outlets and some air through the
windshield defroster outlets.
(Blend): Airflow is divided equally between the
floor outlet and the windshield defroster outlets. The air
conditioning compressor may run to dehumidify the air
to prevent window fogging.

3-7
(Defrost): This setting directs most of the air
through the windshield defroster outlets with air flow
also delivered from the side window and floor outlets.
When in defrost mode, the air conditioning compressor
may run to assist in dehumidifying the air and limit
window fogging.
Mode Buttons
(Outside Air): Press this button to force the
system to use outside air. Press is again to close off the
outside air.
Pressing the outside air button will cancel the
recirculation button.
(Recirculation): Press this button to limit the
amount of outside air entering your vehicle. This is
helpful when you are trying to limit odors entering your
vehicle or attempting to quickly cool down the interior.
Recirculation may be selected with the fan control in
OFF to limit odors, outside air and dust from entering
your vehicle.
Pressing the recirculation button will cancel the outside
air button.
A/C (Air Conditioning):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. When in AUTO, the A/C is automatically engaged
when necessary.
Air conditioning will be automatically disabled when
the outside air temperature drops below a level at which
air conditioning is ineffective.
Mode Knob
-- Automatic Operation
When the system is set for automatic operation,
sensors will control the air delivery mode. Air will
come primarily from the floor or instrument panel
outlets, with some air directed to the windshield to
prevent fogging.
When the system is in AUTO mode, the air conditioning
light will turn on, and the recirculation and outside air
lights turn off. With the system in full auto control
(both the fan and mode knobs in AUTO), you still have
the ability to override any function. However, continually
overriding the outside air or the A/C compressor will limit
the ability of the system to cool the vehicle quickly.

3-8
If you push a button for a function which is not
available, the light next to that button will flash three
times to alert you that it's not available.
To find your comfort zone, start with the 74
F (23
C)
setting and allow about 20 minutes for the system to
adjust the temperature if necessary.
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 of the floor
outlets. As the interior temperature approaches a desired
setting, the fan 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
-level mode) to
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 fan speed
will gradually increase and air will flow from the floor
outlets, with some airflow to the windshield to prevent
fogging under most normal conditions.
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.

3-9 Rear Air Conditioning and Heating Systems
(If Equipped)
If your vehicle has one of these systems, you can
increase and decrease the airflow at the rear vents.
Depending on the system you have and the setting
selected, you can send cooled or heated air to the rear
of the vehicle.
Rear Air Conditioning and Rear Heater
(With Sunroof)
Your vehicle has the rear air conditioning and rear heater
system combination. Controls are provided to regulate
temperature, air delivery location and fan speed.
Front ControlTo adjust the airflow speed, turn the fan control knob
located on the left side to the desired setting.
To regulate the airflow location, adjust the right knob on
the control. Turn the knob clockwise for floor vent
airflow or counterclockwise for headliner vent airflow.
Generally, the instrument panel outlets are used for air
conditioning and the floor vents for heating. The control
knob can be set to any blend setting.
To adjust the air temperature, turn the temperature knob
on the center of the control panel.
For warmer air, turn the knob clockwise toward red. For
cooler air, turn the knob counterclockwise toward blue.

3-10
Rear Air Conditioning (Without Rear Heater)
(If Equipped)
Front Control
To increase and decrease the flow of cooled air to the
rear vents, turn the knob to the fan speed you want.
The knob has three speed positions. To increase the flow
of cooled air, turn the knob toward 3. To decrease the
flow of cooled air, turn it toward 1. To turn the fan off,
turn the knob to OFF.To operate the rear system using the front control, just
turn the knob to the fan position you want.Rear Control
To use the rear control, first turn the front control to
REAR. Then, the rear control can be used to increase
and decrease the airflow.

3-11
Rear Air Conditioning and Rear Heater
(If Equipped)
If your vehicle has the rear air conditioning and rear
heater system combination, controls are provided to
regulate temperature, location and fan speed.
Front Control
To adjust the airflow speed, turn the fan knob located on
the left side to the desired setting.
To activate the second seat control system, turn the fan
knob on the front overhead control to REAR.To regulate the airflow location, adjust the right knob on
the control panel. Turn the knob clockwise for floor vent
airflow or counterclockwise for headliner vent airflow.
Generally, the instrument panel outlets are used for air
conditioning and the floor vents for heating. The knob
can be set to any blend setting.
To adjust the air temperature, turn the temperature knob
on the center of the control panel.
For warmer air, turn the knob clockwise toward red. For
cooler air, turn the knob counterclockwise toward blue.
Rear Control
The rear control works just like the front control. It
allows second seat passengers to adjust the controls as
they desire. To use the rear control, first turn the knob
on the front control panel to REAR.

3-12 Rear Air Conditioning and Heating
Systems with Electronic Climate Control
System (If Equipped)
Front Control
Rear ControlWith this system the rear passengers can control the
temperature of the air flow for the rear seating area. The
climate control has three controls.
To adjust the airflow speed, turn the fan knob located on
the left side of the control panel.
The system also has a front AUTO setting that can
automatically change the temperature of the rear seating
area based on information from the front control. An
OFF setting, located on the front climate control panel,
also allows the driver to turn off the rear passenger seat
controls from the front seat.
To adjust the air temperature, turn the temperature knob
on the center of the control panel clockwise toward
82
F (28
C) for warmer air. Turn the knob
counterclockwise toward 66
F (19
C) for cooler air.
To regulate the airflow location, adjust the right knob
on the control panel. Turn the knob clockwise for floor
outlets airflow or counterclockwise for headliner vent
airflow. Generally, the instrument panel outlets are used
for air conditioning and the floor vents for heating. The
knob can be set to any blend setting.