air condition GMC YUKON 1999 Owner's Manual

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The 1999 GMC Yukon Denali Owner's Manual
1-1 Seats and Restraint SystemsThis section tells you how to use your seats and safety belts properly. It also explains the air bag system.
2-1 Features and ControlsThis section explains how to start and operate your vehicle.
3-1 Comfort Controls and Audio SystemsThis section tells you how to adjust the ventilation and comfort controls and how to operate your audio system.
4-1 Your Driving and the RoadHere you'll find helpful information and tips about the road and how to drive under different conditions.
5-1 Problems on the RoadThis section tells you what to do if you have a problem while driving, such as a flat tire or overheated engine, etc.
6-1 Service and Appearance CareHere the manual tells you how to keep your vehicle running properly and looking good.
7-1 Maintenance ScheduleThis section tells you when to perform vehicle maintenance and what fluids and lubricants to use.
8-1 Customer Assistance InformationThis section tells you how to contact GMC for assistance and how to get service and owner publications.
It also gives you information on ªReporting Safety Defectsº on page 8-10.
9-1 IndexHere's an alphabetical listing of almost every subject in this manual. You can use it to quickly find
something you want to read.

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1-27
When should an air bag inflate?
An air bag is designed to inflate in a moderate to severe
frontal or near
-frontal crash. The air bag will inflate
only if the impact speed is above the system's designed
ªthreshold level.º If your vehicle goes straight into a
wall that doesn't move or deform, the threshold level is
about 9 to 16 mph (14 to 26 km/h). The threshold level
can vary, however, with specific vehicle design, so that
it can be somewhat above or below this range. If your
vehicle strikes something that will move or deform, such
as a parked car, the threshold level will be higher. The
air bag is not designed to inflate in rollovers, side
impacts or rear impacts, because inflation would not
help the occupant.
In any particular crash, no one can say whether an air
bag should have inflated simply because of the damage
to a vehicle or because of what the repair costs were.
Inflation is determined by the angle of the impact and
how quickly the vehicle slows down in frontal or
near
-frontal impacts.
The air bag system is designed to work properly under a
wide range of conditions, including off
-road usage.
Observe safe driving speeds, especially on rough terrain.
As always, wear your safety belt. See ªOff
-Road
Drivingº in the Index for more tips on off
-road driving.What makes an air bag inflate?
In an impact of sufficient severity, the air bag sensing
system detects that the vehicle is in a crash. The sensing
system triggers a release of gas from the inflator, which
inflates the air bag. The inflator, air bag and related
hardware are all part of the air bag modules inside the
steering wheel and in the instrument panel in front of the
right front passenger.
How does an air bag restrain?
In moderate to severe frontal or near
-frontal collisions,
even belted occupants can contact the steering wheel or
the instrument panel. Air bags supplement the protection
provided by safety belts. Air bags distribute the force of
the impact more evenly over the occupant's upper body,
stopping the occupant more gradually. But air bags
would not help you in many types of collisions,
including rollovers, rear impacts and side impacts,
primarily because an occupant's motion is not toward
those air bags. Air bags should never be regarded as
anything more than a supplement to safety belts,
and then only in moderate to severe frontal or
near
-frontal collisions.

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2-73 Air Bag Readiness Light
There is an air bag readiness light on the instrument
panel, which shows AIR BAG. 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 engine,
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
engine or comes on when you are driving, your air bag
system may not work properly. Have your vehicle
serviced right away.
The air bag readiness light should flash for a few
seconds when you turn the ignition key to RUN. If the
light doesn't come on then, have it fixed so it will be
ready to warn you if there is a problem.
Charging System Warning Light
The charging system
warning light should come
on briefly when you turn on
the ignition, before starting
the engine, as a check to
show you it is working.
After the engine starts, the light should go out. If it stays
on or comes on while you are driving, you may have a
problem with your charging system. It could indicate a
problem with the generator drive belt, or some other
charging system problem. Have it checked right away.
Driving while this light is on could drain your battery.
If you must drive a short distance with this light on, it
helps to turn off all your accessories, such as the radio
and the air conditioner.

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2-77
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 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 the SERVICE ENGINE SOON
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.

Light On Steady
-- An emission control system
malfunction has been detected on your vehicle.
Dealer or qualified service center diagnosis and
service may be required.
If the Light Is Flashing
The following may prevent more serious damage to
your vehicle:

Reducing vehicle speed.

Avoiding hard accelerations.

Avoiding steep uphill grades.

If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possible.

3-
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3-1
Section 3 Comfort Controls and Audio Systems
In this section, you'll find out how to operate the comfort control and audio systems offered with your vehicle. Be
sure to read about the particular systems supplied with your vehicle.
3
-2 Comfort Controls
3
-3 Rear Air Conditioning
3
-4 Air Conditioning
3
-5 Heating
3
-5 Ventilation System
3
-6 Defogging and Defrosting
3
-7 Rear Window Defogger
3
-7 Audio Systems
3
-7 Setting the Clock
3
-8AM-FM Stereo with Cassette Tape Player3
-12 CD Adapter Kit
3
-12 Rear Seat Audio (RSA)
3
-14 Remote Compact Disc Player (If Equipped)
3
-16 Console-Mounted CD Changer
3
-19 Theft-Deterrent Feature
3
-21 Understanding Radio Reception
3
-21 Tips About Your Audio System
3
-22 Care of Your Cassette Tape Player
3
-24 Care of Your Compact Discs
3
-24 Fixed Mast Antenna

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3-2
Comfort Controls
Heater and Air Conditioning
Control System
Fan Knob
The knob on the left side of the heating system control
panel controls the fan speed. The knob has four speed
positions. To increase airflow, move the knob toward
HI. To decrease airflow, move it toward LO. To turn the
fan off, move the knob to OFF. If you have the air
conditioner on, moving the fan knob to OFF also turns
off the A/C compressor.
In OFF, while driving, air will flow through the floor
outlets. The mode knob will not redirect the airflow to
other selected outlet positions. This is normal operation
for the OFF position.Temperature Knob
The middle knob on the control panel lets you select the
relative temperature of the air flowing into the passenger
area of your vehicle. This knob will allow you to adjust
the relative air temperature independently of the
function knob setting. 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. The control knob
can be placed in any position between any two mode
settings to blend the flow of air.
VENT: This setting directs air through the
instrument panel outlets.
VENT/HEAT: Use this setting to divide airflow
between the floor outlets and instrument panel outlets.
HEATER: This setting directs air through the
floor outlets.
DEFOG: This setting directs air to the heater
outlets and toward the windshield.

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DEFROST: This setting directs air toward
the windshield.
Rear Air Conditioning
You can increase and decrease the airflow at the rear
vents. You can also send cooled air to the rear of
the vehicle.
Your vehicle has rear air conditioning (without rear
heater). The controls are located above the front and
second seats. The front and rear overhead controls let
you increase and decrease the airflow at the rear vents.
To operate the rear air conditioning system, the front air
conditioning system must be on. With the front air
conditioning system off, the rear system controls can be
used to circulate air in the rear of the vehicle.
To operate the rear system using the front control, just
turn the knob to the blower position you want.

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3-4
To use the rear control, first turn the front control knob
to REAR CNTL. Then, the rear control can be used to
increase and decrease the airflow.
Air Conditioning
On hot days, open the windows long enough to let hot
air inside escape. This reduces the time it takes for your
vehicle to cool down. Then keep your windows closed
for the air conditioner to work its best.
The recirculation button, between the fan and
temperature knobs, allows the air inside your vehicle to
be recirculated. This setting helps to maximize your air
conditioner's performance and your vehicle's fuel
economy. This setting also cools the air the fastest and
can be used to keep unwanted odors and/or dust from
entering the vehicle. When using the air conditioner,
turn off recirculation after the vehicle reaches a
comfortable interior temperature. When the right knob
on the control panel is between HEATER and
DEFROST, the recirculation feature will not function.
The A/C button, between the temperature and mode
knobs, allows the air coming into your vehicle to be
cooled. This setting is useful for normal cooling on hot
days. When you use A/C with the recirculation button
pushed in, turn off recirculation as soon as the vehicle
reaches a comfortable interior temperature.

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With the A/C on, turn the temperature knob to MAX for
maximum cooling. This setting also puts the system in
the recirculation mode and helps to maximize your air
conditioner's performance and your vehicle's fuel
economy. This setting also cools the air the fastest. After
the vehicle's interior reaches a comfortable temperature,
turn the temperature knob clockwise to place the air
conditioning system in the normal mode.
Heating
The heater works best if you keep your windows closed
while using it. On cold days, use the HEATER or
VENT/HEAT setting with the temperature knob in
the red area.
If you use the engine coolant heater before starting your
engine in cold weather, 20
F (
-8
C) or lower, your
heating system will produce warmer air faster, to heat
the passenger compartment in cold weather.
The use of an engine coolant heater also reduces the
time it takes for the engine to reach normal operating
temperature, and shortens the time it takes the heater to
reach full output. For more information, see ªEngine
Coolant Heaterº in the Index.
Ventilation System
For mild outside temperatures when little heating or
cooling is needed, use VENT to direct outside air
through your vehicle. Air will flow through the
instrument panel outlets.
Your vehicle's ventilation system supplies outside air to
the inside of your vehicle when it is moving. With the side
windows closed, air will flow into the front air inlet grilles,
through the vehicle, and out the air exhaust valves.
Outside air will also enter the vehicle when the heater or
the air conditioning fan is running, unless you have the
recirculation button pushed in. For more information on
the recirculation button, see ªAir Conditioningº earlier
in this section.

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Your vehicle has air outlets in the center and on the sides
of your instrument panel. You can move the outlets from
side
-to-side or up and down to direct the flow of air, or
close the outlets altogether. When you close an outlet, it
will increase the flow of air coming out of any outlets
that are open. These outlets do not completely shut off
airflow when in a closed vent position.Ventilation Tips

Keep the hood and front air inlet 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.

When you enter a vehicle in cold weather, turn the
blower fan to HI for a few moments before driving.
This helps clear the intake ducts of snow and
moisture, and reduces 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.

The use of hood air deflectors may adversely
affect the performance of the heating and air
conditioning system.
Defogging and Defrosting
On cool, humid days, use DEFOG to keep the
windshield and side windows clear. Use DEFROST to
remove fog or ice from the windshield in extremely
humid or cold conditions. Use DEFROST with the
temperature knob toward the red area and the fan control
toward HI.