2002 GMC YUKON instrument panel

2-74
When one of the warning lights comes on and stays on
when you are driving, or when one of the gages shows
there may be a problem, check the section that tells you
what to do about it. Please follow this manual's advice.
Waiting to do repairs can be costly
-- and even
dangerous. So please get to know your warning lights
and gages. They're a big help.
Your vehicle also has a driver information system that
works along with the warning lights and gages. See
ªMessage Centerº in the Index.
Safety Belt Reminder Light
When the key is turned to RUN or START, a chime will
come on for about six seconds to remind people to
fasten their safety belts, unless the driver's safety belt is
already buckled.
The safety belt light will
also come on and stay on
for about 20 seconds,
then it will flash for
about 55 seconds.
If the driver's belt is already buckled, neither the chime
nor the light will come on.
Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel, which shows the air bag symbol. The system
checks the air bag's electrical system for malfunctions.
The light tells you if there is an electrical problem.
The system check includes the air bag sensors, the air
bag modules, the wiring and the crash sensing and
diagnostic module. For more information on the air bag
system, see ªAir Bagº in the Index.
This light will come on
when you start your vehicle,
and it will flash for a few
seconds. Then the light
should go out. This means
the system is ready.
If the air bag readiness light stays on after you start the
vehicle or comes on when you are driving, your air bag
system may not work properly. Have your vehicle
serviced right away.

2-88
Here are some situations you may experience with
your fuel gage. None of these indicate a problem with
the fuel gage.

At the gas station, the fuel pump shuts off before the
gage reads full.

It takes a little more or less fuel to fill up than the
fuel gage indicated. For example, the gage may have
indicated the tank was half full, but it actually took a
little more or less than half the tank's capacity to fill
the tank.

The gage goes back to empty when you turn off
the ignition.
Message Center
The message center is located on the left side of the
instrument panel cluster. It gives you important safety
and maintenance facts. When you turn the ignition on,
the entire center lights up for just a few seconds. As
needed, the message center will display one of the
following messages. The message center is capable
of alternating among different messages if needed.
Battery
If this message is displayed
when the engine is running,
you may have a problem
with your charging system.
The battery display will also stay on while the key is in
RUN until the engine is started.
If the message stays on after starting the engine it could
indicate a problem with the generator drive belt, or some
other charging system problem. Have it checked right
away. Driving with this message displayed could drain
your battery.
If you must drive a short distance with this message
displayed, it helps to turn off all your accessories, such
as the radio and the air conditioner.

3-2
Comfort Controls
Standard Comfort Controls
Fan Knob
The knob on the left side of the control panel adjusts the
fan speed. To increase airflow, turn the knob clockwise.
To decrease airflow, turn it counterclockwise. To turn
the fan off, turn the knob to OFF.
Temperature Knob
The middle knob on the control panel lets you select the
temperature of the air flowing into the passenger area.
Turn the knob clockwise toward the red area for warmer
air. Turn the knob counterclockwise toward the blue area
for cooler air.Mode Knob
The right knob on the control panel allows you to
choose the direction of air delivery.
(Vent): This setting directs the air through the
instrument panel outlets.
(Bi-Level): Air is delivered through the floor
outlets as well as the instrument panel outlets. The air
flow can be divided between instrument panel and floor
depending upon where the knob is placed between
the settings.
(Floor): This setting directs most of the air
through the floor outlets, and the rest of the air is
divided between the windshield defroster outlets and the
side window defroster outlets.
(Blend): Airflow is delivered through the floor
outlets, the windshield defroster outlets and the floor
and defrost depending upon where the knob is placed
between the settings.
(Defrost): This setting directs most air through the
windshield defroster outlets, side window defroster
outlets and some through the floor outlets.

3-3 Heater and Air Conditioning Comfort
Controls (If Equipped)
Fan Knob
The knob on the left side of the control panel adjusts the
fan speed. To increase airflow, turn the knob clockwise.
To decrease airflow, turn it counterclockwise. To turn
the fan off, turn the knob to OFF.
Temperature Knob
The middle knob on the control panel lets you select the
temperature of the air flowing into the passenger area.
Turn the knob clockwise toward the red area for warmer
air. Turn the knob counterclockwise toward the blue area
for cooler air.Mode Knob
The right knob on the control panel allows you to
choose the direction of air delivery.
(Vent): This setting directs the air through the
instrument panel outlets and the center floor console
(if equipped).
(Bi-Level): Air is delivered through the
instrument panel outlets and center floor console outlets
(if equipped) as well as the floor outlets. The air flow
can be divided between instrument panel and floor
depending upon where the knob is placed between the
settings. Pressing the A/C button while in this mode
causes cooler air to come out of the instrument panel
outlets and center floor console outlets (if equipped) and
warmer air to come out of the floor outlets.
(Floor): This setting directs most of the air
through the floor outlets and center floor console outlets
(if equipped), as well as some air through the windshield
defroster outlets and side window defroster outlets. If air
from the center floor console outlets is not desired, turn
the vents off at the console.

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.