1999 GMC YUKON air conditioning

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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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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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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.

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Section 6 Service and Appearance Care
Here you will find information about the care of your vehicle. This section begins with service and fuel information,
and then it shows how to check important fluid and lubricant levels. There is also technical information about your
vehicle, and a part devoted to its appearance care.
6
-2 Service
6
-3 Fuel
6
-5 Fuels in Foreign Countries
6
-5 Filling Your Tank
6
-8 Filling a Portable Fuel Container
6
-8 Checking Things Under the Hood
6
-11 Engine Oil
6
-15 Engine Air Cleaner/Filter
6
-17 Automatic Transmission Fluid
6
-20 Rear Axle
6
-21 Four-Wheel Drive
6
-22 Radiator Pressure Cap
6
-23 Thermostat
6
-23 Engine Coolant
6
-27 Power Steering Fluid
6
-28 Windshield Washer Fluid6
-29 Brakes
6
-33 Battery
6
-34 Bulb Replacement
6
-38 Windshield Wiper Blade Replacement
6
-39 Tires
6
-47 Appearance Care
6
-47 Cleaning the Inside of Your Vehicle
6
-50 Care of the Safety Belts
6
-51 Cleaning the Outside of Your Vehicle
6
-54 GM Vehicle Care/Appearance Materials
6
-55 Vehicle Identification Number (VIN)
6
-56 Electrical System
6
-61 Replacement Bulbs
6
-63 Capacities and Specifications
6
-64 Air Conditioning Refrigerants
6
-65 Normal Maintenance Replacement Parts

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Fluid Leak Check
After the vehicle has been parked for awhile, inspect the
surface under the vehicle for water, oil, fuel or other
fluids. Water dripping from the air conditioning system
after it has been used is normal. If you notice fuel leaks
or fumes, the causes should be found and corrected
at once.
Battery
Your new vehicle has an ACDelco Freedom
battery.
When it's time for a new battery, we recommend an
ACDelco Freedom battery. Get one that has the
replacement number shown on the original
battery's label.
Vehicle Storage
If you're not going to drive your vehicle for 25 days or
more, remove the black, negative (
-) cable from the
battery. This will help keep your battery from
running down.
CAUTION:
Batteries have acid that can burn you and gas
that can explode. You can be badly hurt if you
aren't careful. See ªJump Startingº in the Index
for tips on working around a battery without
getting hurt.
Contact your dealer to learn how to prepare your vehicle
for longer storage periods.
Also, for your audio system, see ªTheft
-Deterrent
Featureº in the Index.