2003 GMC YUKON DENALI air condition

Outlet Adjustment
Use the air outlets located in the center and on the side
of your instrument panel to direct the airflow.
Your vehicle has air outlets that allow you to adjust the
direction and amount of airflow inside the vehicle.
Move the louvers up or down. Use the thumbwheel next
to or underneath the outlet
to close the louvers. For
the most efficient airflow and temperature control, keep
the outlet in the fully opened position.
Operation Tips
e
e
Keep the hood and front air inlets free of ice, snow,
or any other obstruction (such as leaves). The
heater and defroster will work far better, reducing
the chance of fogging the inside of your windows.
Keep the air path under the front seats clear
of objects. This helps air to circulate throughout
your vehicle.
Adding outside equipment
to the front of your
vehicle, such as hood-air deflectors, etc., may affect
the performance of the heating and air conditioning
system. Check with your dealer before adding
equipment to the outside of your vehicle.
Rear Climate Control System
With this system the front or rear passengers can
control the air temperature, air flow and fan speed for
the rear seat passengers. The climate control has
an overhead control near the driver and a control on the
back of the center console.
Driver Overhead Control
I/
I
Front Controls
To control the rear climate control from the front seat
position, use the driver overhead control. The rear
console control must be on.
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AUX: Turn the knob, located on the left side of the
control panel, to this position
to allow the rear seat
passengers
to have control over the rear climate control
system. See “Rear Passenger Console Control’’ later
for more information.
0 (Off): Turn the knob, located on the left side of the
control panel,
to this position to turn the rear climate
control system
off.
@ (Fan): To adjust the airflow speed, turn the fan
knob located on the left side of the control panel
to the
desired setting. Choose AUTO
if you want the system
to automatically choose the fan speed to maintain
a selected temperature. See “Auto Mode” later in this
section for more information on using this feature.
“F (“C): To adjust the air temperature, turn the
temperature knob on the center of the control panel. For
cooler or warmer air turn the knob counterclockwise
toward
66°F (1 9°C) or clockwise toward 82°F (27°C).
To regulate the airflow direction, adjust the right knob on
the control panel. Turn the knob clockwise for floor
vent airflow or counterclockwise for headliner vent
airflow. Generally, the upper vents are used for air
conditioning and the floor vents for heating. The knob
can be set
to any blend setting. Choose AUTO if
you want the system to automatically regulate the
airflow. See “Auto Mode” later in this section for more
information on using this feature.
Rear Passenger Console Control
To control the rear climate control from the rear
passenger seat position, use the rear passenger console
control. The driver overhead control fan knob must be
set
to the AUX position.
Rear Controls
The rear seat controls have the following settings:
0 (OnIOff): Press this button to turn the rear seat
Comfort controls on or
off when the front overhead
control is set
to AUX.
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If the word OFF or the off symbol is lit on the air bag
status indicator,
it means that the passenger sensing
system has turned
off the right front passenger’s frontal
air bag. See Passenger Sensing System on page
7 -8 7
for more on this, including important safety information.
If, after several seconds, all status indicator lights
remain on, or
if there are no lights at all, there may be a
problem with the lights or the passenger sensing
system. See your dealer for service.
__ -he ofl ..jdicator and the air bag readiness
light ever come on together, it means that
something may be wrong with the air bag
system.
If this ever happens, have the vehicle
serviced promptly, because an adult-size
person sitting in the right front passenger seat
may not have the protection of the frontal air
bag. See “Air Bag Readiness Light” in the
Index.
Charging System Light
The charging system light
will come on briefly when you turn on the ignition,
but the engine is
not
running, as a check to
show you it
is working.
It should go out once the engine is running. If it stays
on, or comes on while you are driving, you may have a
problem with the charging system.
It could indicate
that you have problems with a generator drive belt, or
another electrical problem. Have it checked right
away. Driving while this light is on could drain your
battery.
When this light comes on the DIC will also display the
battery not charging message. See
DIC Warnings
and Messages
on page 3-52.
If you must drive a short distance with the light on, be
certain to turn
off all your accessories, such as the radio
and air conditioner.
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A temporary solution to hotter transmission operating
temperatures may be
to let the transmission cool down.
If the transmission is operated at higher temperatures
on a frequent basis, see
Scheduled Maintenance
on page
6-5 for the proper transmission maintenance
intervals.
Malfunction Indicator Lamp
Check Engine Light
Your vehicle is equipped
with
a computer which
monitors operation of the
fuel, ignition and emission
control systems.
This system is called OBD
II (On-Board
Diagnostics-Second Generation) and is intended to
assure that emissions are at acceptable levels for the
life of the vehicle, helping
to produce a cleaner
environment. The Check Engine light comes on
to
indicate that there is a problem and service is required.
Malfunctions often will be indicated by the system
before any problem is apparent. This may prevent more
serious damage
to your vehicle. This system is also
designed to
assist your service technician in correctly
diagnosing any malfunction.
Notice: If you keep driving your vehicle with this
light on, after a while, your emission controls
may not work as well, your fuel economy may not
be as good and your engine may not run as
smoothly. This could lead to costly repairs that may
not be covered by your warranty.
Notice: Modifications made to the engine,
transmission, exhaust, intake or fuel system of your
vehicle or the replacement of the original tires
with other than those of the same Tire Performance
Criteria (TPC) can affect your vehicle’s emission
controls and may cause this light to come on.
Modifications to these systems could lead to costly
repairs not covered by your warranty. This may
also result
in a failure to pass a required Emission
Inspection/Maintenance test.
This light should come on, as a check to show you it is
working, when the ignition is on and the engine is
not running. If the light doesn’t come on, have it
repaired. This light will also come on during
a
malfunction in one of two ways:
Light Flashing - A misfire condition has been
detected.
A misfire increases vehicle emissions
and may damage the emission control system on
your vehicle. Dealer or qualified service center
diagnosis and service may be required.
3-38

When the Stabilitrak@system has been turned off you
may still hear system noises as a result of the
brake-traction control coming on.
It is recommended to leave the system on for normal
driving conditions, but it may be necessary
to turn
the system
off if your vehicle is stuck in sand, mud, ice
or snow, and you want
to “rock” your vehicle to
attempt to free it. It may also be necessary to turn off
the system when driving in extreme off-road conditions
where high wheel spin is required. See If
You Are
Stuck: In Sand, Mud, Ice or Snow on page
4-4 1.
Traction Control Operation
The traction control system is part of the
Stabilitrak@system. Traction control limits wheel spin by
reducing engine power
to the wheels (engine speed
management) and by applying brakes
to each individual
wheel (brake-traction control) as necessary.
The traction control system is enabled automatically
when you start your vehicle, and it will activate
and display the TRACTION ACTIVE message in the
Driver Information Center (DIC)
if it senses that any of
the wheels are spinning or beginning to lose traction
while driving. If you turn
off Stabilitrak@, only the
brake-traction control portion
of traction control will
work. The engine speed management will be disabled.
In this state, engine power is not reduced automatically
and the driven wheels can spin more freely. This
can cause the brake-traction control
to activate
constantly. For more information on the traction active
message, see Driver Information Center (DIC) on
page
3-43.
Notice: If the traction off light comes on due to
heavy braking and/or because the traction control
system has been continuously active, do not allow
the wheel@) of one axle to spin excessively.
If you
do, you may be causing damage to your transfer
case. This could lead to costly repairs not covered by
your warranty.
If the brake-traction control system activates constantly
or
if the brakes have heated up due to high speed
braking, the brake-traction control will be automatically
disabled. The system will come back on after the
brakes have cooled. This can take up
to two minutes ot
longer depending on brake usage.
Notice: Don’t allow the wheel(s) of one axle to spin
excessively when the traction
off, ABS and brake
lights are on and the
SERVICE STABILITY MESSAGE
is displayed. In this situation, damage to the transfer
case
is possible. This could lead to costly repairs not
covered by your warranty. You should immediately
reduce engine power until the lights and messages
are no longer displayed.
4-1 0

Automatic Level Control
The automatic level control rear suspension comes as a
part of the AutorideTMsuspension. See AutorideTM on
page
4-46.
This type of level control is fully automatic and will
provide a better leveled riding position as well as better
handling under a variety of passenger and loading
conditions. An air compressor connected
to the rear
shocks will raise or lower the rear of the vehicle
to maintain proper vehicle height. The system is
activated when the ignition key
is turned to RUN and
will automatically adjust vehicle height thereafter.
The system may exhaust (lower vehicle height) for up
to
10 minutes after the ignition key has been turned to
OFF. You may hear the air compressor operating when
the height is being adjusted.
If a weight-distributing hitch is being used, it is
recommended
to allow the shocks to inflate, thereby
leveling the vehicle prior to adjusting the height.
AutorideTM
The AutorideTM feature provides superior vehicle ride
and handling under a variety
of passenger and loading
conditions.
The system is fully automatic and
uses a computer
controller
to continuously monitor vehicle speed, wheel
to body position, IifVdive and steering position of the
vehicle. The controller then sends signals to each shock
absorber
to independently adjust the damping level to
provide the optimum vehicle ride.
AutorideTM also interacts with the towlhaul mode that,
when activated, will provide additional control of
the shock absorbers. This additional control results in
better ride and handling characteristics when the vehicle
is loaded or towing a trailer. See "Tow/Haul Mode"
under Towing a Trailer on page
4-47 for more
information.
4-46

California Fuel
If your vehicle is certified to meet California Emission
Standards (see the underhood emission control label), it
is designed
to operate on fuels that meet California
specifications.
If this fuel is not available in states
adopting California emissions standards, your vehicle
will operate satisfactorily on fuels meeting federal
specifications, but emission control system performance
may be affected. The malfunction indicator lamp may
turn on (see Malfunction Indicator Lamp on page
3-38 )
and your vehicle may fail a smog-check test. If this
occurs, return
to your authorized GM dealer for
diagnosis.
If it is determined that the condition is caused
by the type of fuel used, repairs may not be covered
by your warranty.
Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent engine and fuel system deposits from forming,
allowing your emission control system
to work
properly. You should not have
to add anything to your
fuel. Gasolines containing oxygenates, such as ethers and ethanol, and reformulated gasolines may be
available in your area to contribute
to clean air.
General Motors recommends that you use these
gasolines, particularly
if they comply with the
specifications described earlier.
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Notice: Your vehicle was not designed for fuel that
contains methanol. Don’t use fuel containing
methanol. It can corrode metal parts in your fuel
system and also damage the plastic and rubber
parts. That damage wouldn’t be covered under your
warranty.
Some gasolines that are not reformulated for low
emissions may contain an octane-enhancing additive
called methylcyclopentadienyl manganese tricarbonyl
(MMT); ask the attendant where you buy gasoline
whether the fuel contains MMT. General Motors does
not recommend the use of such gasolines. Fuels
containing MMT can reduce the life of spark plugs and
the performance of the emission control system may
be affected. The malfunction indicator lamp may turn on.
If this occurs, return to your authorized GM dealer for
service.
Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel may be hard
to find. Never use leaded gasoline or any other fuel
not recommended in the previous text on fuel. Costly
repairs caused by use of improper fuel wouldn’t be
covered by your warranty.
To check the fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you’ll be driving.

Adding Coolant
If you need more coolant, add the proper DEX-COOL@
coolant mixture
at the surge tank, but only when the
engine
is cool.
1 “J can be burned if you sb... coolant on hot
engine parts. Coolant contains ethylene glycol, and
it will burn if the engine parts are hot
enough. Don’t spill coolant on a hot engine.
When replacing the pressure cap, make sure it is
hand-tight.
Coolant Surge Tank Pressure Cap
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank. See Engine
Compartment Overview on page
5-12 for more
information on location.
Notice: Your pressure cap is a pressure-type cap
and must be tightly installed to prevent coolant
loss
and possible engine damage from overheating.
See “Capacities and Specifications” for more
information.
Engine Overheating
You will find a coolant temperature gage on your
vehicle’s instrument panel. See Engine Coolant
Temperature Gage
on page 3-36. in addition, yoti ill
find a LOW COOLANT, ENGINE COOLANT HOT,
ENGINE OVERHEATED and a REDUCED ENGINE
POWER message in the DIC on the instrument panel.
See DIC Warnings and Messages on page
3-52.
Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
REDUCED ENGINE POWER message is displayed, an
overheat protection mode which alternates firing
groups of cylinders helps prevent engine damage.
In
this mode, you will notice a loss in power and engine
performance. This operating mode allows your vehicle to
be driven
to a safe place in an emergency. Driving
extended miles (km) and/or towing a trailer in the
overheat protection mode should be avoided.
Notice: After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair the cause of coolant
loss, change the oil and reset the oil
life system. See “Engine Oil” in the Index.
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