2002 GMC YUKON heating

2-14
Liftgate
CAUTION:
It can be dangerous to drive with the liftgate
glass, liftgate or rear doors open because carbon
monoxide (CO) gas can come into your vehicle.
You can't see or smell CO. It can cause
unconsciousness and even death.
If you must drive with the liftgate glass, liftgate
or rear doors open or if electrical wiring or other
cable connections must pass through the seal
between the body and the liftgate glass, liftgate
or rear doors:

Make sure all other windows are shut.

Turn the fan on your heating or cooling
system to its highest speed with the setting
on VENT or OUTSIDE AIR. That will
force outside air into your vehicle. See
ªComfort Controlsº in the Index.

If you have air outlets on or under the
instrument panel, open them all the way.
See ªEngine Exhaustº in the Index.
Liftgate Glass and Liftgate
To open a mechanical lock system from the outside,
insert the key into the lock and turn it counterclockwise
to unlock the glass and liftgate.
The liftgate glass can be opened using the button on the
liftgate after the doors have been unlocked. This can be
done by using either the power door locks or the remote
keyless entry system.
To open the entire liftgate, lift the handle located in the
center of the door.
To lock a power lock system from the outside, insert the
key into the lock button and turn clockwise. All doors
will lock. You may also use the keyless entry system
or the power door locks to lock the liftgate and
liftgate glass.

2-61
Your vehicle has a Center High-Mounted Stoplamp
(CHMSL) located above the glass or above the rear
load doors.
If items are loaded on the roof of the vehicle,
care should be taken not to block or damage the
CHMSL unit.
Ashtrays and Cigarette Lighter
Front Ashtray
The front ashtray is located near the center of the
instrument panel. Pull on the bottom of the ashtray door
to open it.
NOTICE:
If you store paper or other things that burn in
your ashtrays, they could be set on fire by
cigarettes or other smoking materials. That could
cause a fire and possibly damage your vehicle. Do
not store papers and other things that burn in
your ashtrays.
To remove the front ashtray, press the retainer spring
and pull the ashtray toward you. To replace the ashtray,
place the ashtray on the slides at the side of its location
in the instrument panel. Then slide the ashtray back to
its original position.
To use the cigarette lighter, push it in all the way, and let
go. When it's ready, it will pop back out by itself.
NOTICE:
Holding a cigarette lighter in with your hand
while it's heating can make it overload, damaging
the lighter and the heating element. Just push the
lighter all the way in and let go. When it's done,
it will pop back out by itself.
Sun Visors
To block out glare, you can swing down the top and
bottom visors (if equipped). You can also swing the
bottom visor from side
-to-side. Your visors may have
an extension that can be pulled out for additional
glare protection.

2-80 Engine Coolant Temperature Gage
United States Canada
This gage shows the engine coolant temperature.
It also provides an indicator of how hard your vehicle is
working. During a majority of the operation, the gage
will read 210
F (100
C) or less. If you are pulling a
load or going up hills, it is normal for the temperature to
fluctuate and approach the 250
F (122
C) mark. If the
gage reaches the 260
F (125
C) mark, it indicates that
the cooling system is working beyond its capacity.
See ªEngine Overheatingº in the Index.
Transmission Temperature Gage
(If Equipped)
United States Canada
Your vehicle may be equipped with a transmission
temperature gage.
When your ignition is on, the gage shows the temperature
of the transmission fluid. The normal operating range is
from 100
F (38
C) to about 265
F (130
C).

2-91 Low Coolant
This message is displayed
when the cooling system is
low on coolant.
The engine may overheat. See ªEngine Coolantº in the
Index and have your vehicle serviced as soon as you can.
Check Coolant Temp
This message is displayed
when the cooling system
temperature gets hot.
Check the coolant temperature gage and the coolant
level. See ªEngine Coolantº and ªEngine Coolant
Temperature Gageº in the Index. See ªEngine
Overheatingº in the Index for further information.
Engine Overheated
This message is displayed
when the cooling system
temperature gets too hot.
This message will be displayed after the air conditioning
system has automatically turned off for the engine
coolant protection mode. See ªEngine Overheatingº
in the Index for further information.
Reduced Engine Power
This message is displayed
when the cooling system
temperature gets too hot
and the engine further
enters the engine coolant
protection mode.
If your vehicle is equipped with the 8.1L engine, this
light may come on because of an electronic throttle
control system fault. See ªEngine Overheatingº in the
Index for further information.

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.

3-9 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.

3-11
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.