air GMC YUKON 2004 Service Manual

)(Bi-Level):Air is delivered through the oor outlets
as well as the instrument panel outlets. The ow can
be divided between vent and oor outlets depending
upon where the knob is placed between the settings.
6(Floor):This setting directs most of the air through
the oor outlets, and the rest of the air is divided
between the windshield defroster outlets and the side
window defroster outlets.
W(Defog):Airow is delivered through the oor
outlets, the windshield defroster outlets and the side
window defroster outlets. The air ow can be divided
between oor and defrost depending upon where
the knob is placed between the settings.
1(Defrost):This setting directs most air through the
windshield defroster outlets, side window defroster
outlets and some through the oor outlets.
Dual Climate Control System
With this system you can control the heating, cooling
and ventilation for your vehicle.
9(Fan):Turn the left knob clockwise or
counterclockwise to increase or decrease the fan speed.
Turn the knob to the off position to turn off the fan. If
the knob is in off outside air will still enter the vehicle,
and will be directed based on the position of the
mode knob. The temperature can also be adjusted
using the temperature levers.
Turn the right knob clockwise or counterclockwise to
direct the airow inside of your vehicle.
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To change the current mode, select one of the following:
H(Vent):This mode directs air to the instrument
panel vents.
)(Bi-Level):This mode directs half of the air to the
instrument panel vents; then directs most of the
remaining air to the oor vents. A little air is directed
toward the windshield and the side window vents. Cooler
air is directed to the upper vents and warmer air to the
oor vents.
6(Floor):This mode directs most of the air to the
oor vents with a little air directed to the windshield and
the side window vents.
h(Recirculation):The recirculation mode is used to
recirculate the air inside of your vehicle. Use this mode to
help prevent outside odors and/or dust from entering your
vehicle or to help cool the air inside of your vehicle more
quickly. Press this button to turn the recirculation mode
on or off. The light on the recirculation button will
illuminate. Recirculation cannot be used in oor, blend or
defrost modes. An indicator on the button will light up,
ash three times and turn off when recirculation is
selected in these modes.The air-conditioning compressor
will also come on when this mode is activated. While in
recirculation mode the windows may fog when the
weather is cold and damp. To clear the fog, select either
the blend or defrost mode and increase fan speed.Temperature Control
Driver’s Side:The lever on the left side of the climate
control panel is used to raise or lower the temperature
on the driver’s side of the vehicle. This lever also adjusts
the temperature to the center console outlets (if
equipped).
Passenger’s Side:The lever on the right side of the
climate control panel is used to raise or lower the
temperature on the passenger’s side of the vehicle.
#(Air Conditioning):Press this button to turn the
air-conditioning system on or off. When the button is
pressed, an indicator light will come on and the system
will begin to cool and dehumidify the air inside of your
vehicle. You may notice a slight change in engine
performance when the air conditioning compressor shuts
off and turns on again. This is normal.
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Defogging and Defrosting
Fog on the inside of the windows is a result of high
humidity (moisture) condensing on the cool window
glass. This can be minimized if the climate control
system is used properly. There are two modes to choose
from to clear fog or frost from your windshield. Use
the defog mode to clear the windows of fog or moisture
and warm the passengers. Use the defrost mode to
remove fog or frost from the windshield more quickly.
Turn the right knob clockwise or counterclockwise
to select one of the following modes:
-(Defog):This mode directs the air to the oor
outlets, windshield and the side window vents. The air
conditioning compressor will run automatically to
dehumidify the air to prevent window fogging. The
recirculation mode cannot be selected while in the defog
mode.
1(Defrost):This mode directs most of the air to the
windshield and the side window vents, with only a
little air directed to the oor vents. The air conditioning
compressor will run automatically to dehumidify the
air to prevent window fogging. The recirculation mode
cannot be selected while in defrost mode.
Do not drive the vehicle until all the windows are clear.
Rear Window Defogger
The lines you see on the rear window warm the glass.
The rear window defogger uses a warming grid to
remove fog from the rear window.
<(Rear):Press this button to turn the rear window
defogger on or off. An indicator light in the button
will come on to let you know that the rear window
defogger is activated.
The rear window defogger will automatically turn off
several minutes after the button is pressed. Pressing the
button while the defogger is running can also turn off
the defogger.
If your vehicle is equipped with heated mirrors this
button will activate them.
Notice:Don’t use anything sharp on the inside of
the rear window. If you do, you could cut or damage
the warming grid, and the repairs wouldn’t be
covered by your warranty. Do not attach a temporary
vehicle license, tape, a decal or anything similar
to the defogger grid.
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Outlet Adjustment
Use the air outlets located
in the center and on the
side of your instrument
panel to direct the airow.
Your vehicle has air outlets that allow you to adjust the
direction and amount of airow 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 airow and temperature control, keep
the outlet in the fully opened position.
Rear seat outlets can be used to adjust airow toward
either seating area, the oor or upward. Move the center
louvers up or down to direct the airow.
Operation Tips

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 deectors, 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.
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Dual Automatic Climate Control
System
With this system, you can control the heating, cooling
and ventilation in your vehicle. Your vehicle also
has a ow-through ventilation system described later in
this section.
You can select different climate control settings for the
driver and passengers.
Driver’s Side Temperature Knob
The driver’s side knob is used to adjust the temperature
of the air coming through the system on the driver’s
side. The temperature can be adjusted even if the
system is turned off. This is possible since outside air
will always ow through the system as the vehicle
is moving forward unless it is set to recirculation mode.
See “Recirculation” later in this section.
Turn the knob counterclockwise or clockwise to lower or
increase the cabin temperature. The display will show
the temperature setting decreasing or increasing and an
arrow pointing to the driver will be displayed under
and to the left of the temperature setting.
Passenger’s Side Temperature Knob
The passenger’s side knob can be used to change the
temperature of the air coming through the system
on the passenger’s side of the vehicle. The temperature
can be adjusted even if the system is turned off. This
is possible since outside air will always ow through the
system as the vehicle is moving forward unless it is
set to recirculation mode. See “Recirculation” later in this
section.
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Turn the knob counterclockwise or clockwise to lower or
increase the cabin temperature. The display will show
the temperature setting decreasing or increasing and an
arrow pointing to the passenger will be displayed
under and to the right of the temperature setting.
The passenger’s temperature setting can be set to
match the driver’s temperature setting by pressing and
holding the AUTO button for four seconds. Both the
driver and passenger arrows will be displayed.
Automatic Operation
AUTO (Automatic):When automatic operation is
active the system will control the inside temperature, the
air delivery, and the fan speed.
Use the steps below to place the entire system in
automatic mode:
1. Press the AUTO button.
When AUTO is selected, the display will change to
show the current driver’s set temperature, delivery
mode and fan speed. Press the AUTO button again
within ve seconds to display the passenger’s set
temperature.If the driver and passenger’s temperature settings
are not the same, the opposite side temperature
setting will be displayed for an additional ve
seconds. To make the passenger’s temperature the
same as the driver’s press and hold the AUTO
button for about four seconds.
When AUTO is selected, the air conditioning
operation and air inlet will be automatically
controlled. The air conditioning compressor will run
when the outside temperature is over about
40°F (4°C). The air inlet will normally be set to
outside air. If it’s hot outside, the air inlet may
automatically switch to recirculate inside air to help
quickly cool down your vehicle. The light on the
button will illuminate in recirculation.
2. Set the driver’s and passenger’s temperature.
To nd your comfort setting, start with a 74°F (23°C)
temperature setting and allow about 20 minutes
for the system to regulate. Turn the driver’s or
passenger’s side temperature knob to adjust the
temperature setting as necessary. If you choose the
temperature setting of 60°F (15°C) the system
will remain at the maximum cooling setting. If you
choose the temperature setting of 90°F (32°C)
the system will remain at the maximum heat setting.
Choosing either maximum setting will not cause
the vehicle to heat or cool any faster.
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Be careful not to cover the sensor located on the
top of the instrument panel near the windshield. This
sensor regulates air temperature based on sun
load, and also turns on your headlamps.
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 engine
coolant temperature. Pressing the fan switch will
override this delay and change the fan to a selected
speed.
9(Off):Press this button to turn off the entire climate
control system. Outside air will still enter the vehicle, and
will be directed to the oor. This direction can be changed
by pressing the mode button. The temperature can also
be adjusted using either temperature knob. Press the up
or down arrows on the fan switch, the defrost button, the
AUTO button, or the air conditioning button to turn the
system on when it is off.
Manual Operation
You may manually adjust the air delivery mode or fan
speed.
w9x(Fan):The switch with the fan symbol allows
you to manually adjust the fan speed. Press the up
arrow to increase fan speed and the down arrow
to decrease fan speed.
Pressing this button when the system is off will turn the
system on.
C(Mode):Press this button to manually change the
direction of the airow in your vehicle; keep pressing the
button until the desired mode appears on the display.
If you press the mode button to select an air delivery
mode, the display will change to show you the selected
air mode delivery. The display will then show the current
status of the system. When the system is turned off, the
display will go blank after displaying the current status of
the system.
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H(Panel):This setting will deliver air to the
instrument panel outlets.
)(Bi-Level):This setting will deliver warmer air to the
oor and cooler air to the instrument panel outlets.
6(Floor):This setting will deliver air to the oor
outlets.
-(Defog):See “Defogging and Defrosting” later in
this section.
@(Recirculation):Press this button to limit the
amount of outside air entering your vehicle. The light on
the recirculation button will glow. This is helpful when you
are trying to limit odors entering your vehicle and for
maximum air conditioning performance in hot weather.
Press this button again to allow outside air to enter the
vehicle. The light on the recirculation button will go off.
Pressing this button also cancels the auto recirculation
feature. To resume the auto recirculation function, press
the AUTO button. Each time the vehicle is started, the
system will revert to the auto recirculation function.If you select recirculation while in defrost, defog or oor,
the light in the button will ash and then go out to let you
know that this is not allowed. This is normal and helps to
prevent fogging.
When the weather is cool or damp, operating the system
in recirculation for extended periods of time may cause
fogging of the vehicle’s windows. To clear the fog, select
either defog or front defrost.
You may also notice that the A/C compressor will run
while in recirculation mode. This is normal and helps to
prevent fogging.9(Off):Press this button to turn off the entire climate
control system. Outside air will still enter the vehicle, and
will be directed to the oor. This direction can be changed
by pressing the mode button. The temperature can also
be adjusted using either temperature knob. Press the up
or down arrows on the fan switch, the defrost button, the
AUTO button, or the air conditioning button to turn the
system on when it is off.
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Display
If you press the MODE button to select an air delivery
mode, the display will change to show you the selected
air delivery mode. After ten seconds, the display will
change to show the driver temperature setting and the
selected mode.
If you press the up or down arrows on the fan switch,
the display will change to show the selected fan speed.
After ten seconds, the display will change to show
the driver temperature setting and the selected mode.
Whenever you press AUTO, the display will change
to show the following:
The current driver’s set temperature and an arrow
for ve seconds
The current passenger’s set temperature setting
and an arrow for ve seconds
The automatic air delivery mode and fan speed
If the driver’s and passenger’s temperature settings are
the same when AUTO is pressed, the temperature
setting and both arrows will be displayed for ve
seconds along with the automatic air delivery mode and
fan speed. After the ve second update, the display
will change to show the temperature setting, both arrows
and AUTO.
Air Conditioning
#
(Air Conditioning):Press this button to turn the air
conditioning (A/C) compressor on and off. The snowake
symbol will appear on the display when the A/C is on.
Pressing this button when the outside temperature is too
cool for air conditioning will make the snowake symbol
ash three times and then turn off to let you know the air
conditioning mode is not available. If the air conditioning
is on and the outside temperature drops below a
temperature which is too cool for air conditioning to be
effective, the snowake symbol will turn off to let you
know the air conditioning mode has been canceled.
^(Air Conditioning Off):On some vehicles, when
you turn the air conditioning off, this symbol will appear
on the display. If your vehicle does not have this
symbol, the snowake symbol will turn off to let you
know the air conditioning is off.
When air conditioning is selected or in AUTO mode, the
system will run the air conditioning automatically to cool
and dehumidify the air entering the vehicle. If you select
A/C off while in front defrost, defog or recirculation, the
A/C snowake symbol will turn off, but the A/C
compressor will still run to help prevent fogging.
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On hot days, open the windows long enough to let hot
inside air 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.
On cool, but sunny days while using manual operation
of the automatic system, use bi-level to deliver warm
air to the oor and cooler air to the instrument
panel outlets. To warm or cool the air delivered, turn the
temperature knob to the desired setting.
In AUTO mode the system will cool and dehumidify the
air inside the vehicle. Also while in AUTO mode, the
system will maximize its performance by using
recirculation as necessary.
Heating
On cold days when using manual operation of the
automatic system, choose oor mode to deliver air to
the oor outlets. To warm or cool the air delivered, turn
the temperature knob to the desired setting.
If you want to use the automatic mode, press
AUTO and adjust the temperature by turning the
temperature knob.
The heater works best if you keep the windows closed
while using it.
Defogging and Defrosting
You can use either defog or front defrost to clear fog or
frost from your windshield. Use the defog mode to
clear the windows of fog or moisture. Use the front
defrost button to defrost the front windshield.
-(Defog):Use this setting to clear the windows of fog
or moisture. Press the mode button to select this
setting. This setting will deliver air to the oor and
windshield outlets.
0(Front Defrost):Press the front defrost button to
defrost the windshield. The system will automatically
control the fan speed if you select defrost from AUTO
mode. If the outside temperature is 40°F (4°C) or
warmer, your air conditioning compressor will
automatically run to help dehumidify the air and dry the
windshield.
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