2008 CHEVROLET TAHOE air conditioning

The interior temperature sensors located in the headliner
above the driver side seat and if equipped, in the
headliner above the second row seats measure the
temperature of the air inside the vehicle.
There is also an exterior temperature sensor located
behind the front grille. This sensor reads the outside air
temperature and helps maintain the temperature
inside the vehicle. Any cover on the front of the vehicle
could cause a false reading in the displayed
temperature.
The climate control system uses the information from
these sensors to maintain your comfort setting by
adjusting the outlet temperature, fan speed, and the air
delivery mode. The system may also supply cooler
air to the side of the vehicle facing the sun. The
recirculation mode will also be used as needed to
maintain cool outlet temperatures.
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 clear
fog or frost from your windshield.
Use the mode up and down arrows to select the defog
or defrost modes.
-(Defog):The defog mode is used to clear the
windows of fog or moisture and warm the passengers.
This mode directs air to the windshield, oor outlets,
and side window vents. When this mode is selected,
the system turns off recirculation and runs the air
conditioning compressor unless the outside temperature
is close to freezing. The recirculation mode cannot be
selected while in the defog mode. Do not drive the
vehicle until all the windows are clear.
0(Defrost):Press this button to remove fog or frost
from the windshield more quickly. This mode directs
a portion of the air to the windshield and side window
vents and some to the oor vents. In this mode, the
system will automatically force outside air into the
vehicle. The recirculation mode cannot be selected while
in the defrost mode. The air conditioning compressor
will run automatically in this setting, unless the outside
temperature is close to freezing. Do not drive the
vehicle until all the windows are clear.
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Rear Window Defogger
The rear window defogger uses a warming grid to
remove fog from the rear window.
<(Rear Window Defogger):Press this button to
turn on the rear window defogger. It will automatically
turn off several minutes after it has been activated.
The defogger can also be turned off by pressing
the button again or by turning off the engine. Do not
drive the vehicle until all the windows are clear.
If your vehicle has heated outside rearview mirrors, the
mirrors will heat to help clear fog or frost from the
surface of the mirror when the rear window defog button
is pressed.
Notice:Do not use a razor blade or sharp object to
clear the inside rear window. Do not adhere
anything to the defogger grid lines in the rear glass.
These actions may damage the rear defogger.
Repairs would not be covered by your warranty.
Outlet Adjustment
Use the air outlets located in the center and on the side
of your instrument panel 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.
When you enter a vehicle in cold weather, press the
fan up button to the maximum fan level before
driving. This helps clear the intake ducts of snow
and moisture, and reduces the chance of fogging
the inside of your window.
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, 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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Rear Air Conditioning and Heating
System
If your vehicle has this system, the rear controls are
three knobs located in the headliner. The system can
be controlled from the front controls as well as the rear
controls.
To turn the system on, press the AUX button on the
front climate control system, an indicator will be
lit. Pressing the AUX button the rst time will turn the
rear system on in a mimic mode. In this mode, the
airow in the rear will be approximately the same
direction, temperature, and fan speed as the front.
Pressing the AUX button again will turn the rear system
and the indicator off.
If the rear controls are adjusted, the system will enter a
rear independent mode. Airow in the rear will then
be directed according to the settings of rear controls.
The rear system can be turned off by pressing the
AUX button on the front climate control system and the
indicator will turn off.
Fan Knob
Turn the left knob clockwise or counterclockwise to
increase or decrease the fan speed. Turn the knob all
the way counterclockwise to turn the rear system off.
Temperature Knob
The middle knob on the control panel lets you select
the temperature of the air owing into the passenger
area. Turn the knob clockwise toward the red area for
warmer air. Turn the knob counterclockwise toward
the blue area for cooler air.
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Mode Knob
The right knob on the control panel allows you to
choose the direction of air delivery.
H(Vent):This setting directs the air through the
headliner outlets.
)(Bi-Level):Air is delivered through the oor outlets
as well as the headliner outlets. The rear system
oor outlets are located directly behind the second row
seats. 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. The rear system oor outlets are
located directly behind the second row seats.
Rear Air Conditioning and Heating
System and Electronic Climate
Controls
For vehicles with the rear heat and air conditioning
controls, they are integrated with the rear seat audio
controls located in the center console. The system can
be controlled from the front controls as well as the
rear controls.
To turn the system on, press the AUX button on the
front climate control system, an indicator will be
lit. Pressing the AUX button the rst time will turn the
rear system on in a mimic mode. In this mode, the
airow in the rear will be approximately the same
direction, temperature, and fan speed as the front.
Pressing the AUX button again turns the rear system
and the indicator off.
If the rear controls are adjusted, the system enters a
rear independent mode. Airow in the rear will then
be directed according to the settings of rear controls.
The rear system can be turned off by pressing the
AUX button on the front climate control system and the
indicator will turn off.
If the indicator in the front AUX button is off, the rear
system is off.
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CHECK TIRE PRESSURE
This message displays when the pressure in one or
more of the vehicle’s tires needs to be checked.
This message also displays LEFT FRONT, RIGHT
FRONT, LEFT REAR, or RIGHT REAR to indicate which
tire needs to be checked. You can receive more than
one tire pressure message at a time. To read the other
messages that may have been sent at the same
time, press the set/reset button or the trip odometer
reset stem. If a tire pressure message appears on the
DIC, stop as soon as you can. Have the tire pressures
checked and set to those shown on the Tire Loading
Information label. SeeTires on page 5-66,Loading the
Vehicle on page 4-35, andInflation - Tire Pressure
on page 5-74. The DIC also shows the tire pressure
values. See “DIC Operation and Displays (With
DIC Buttons)” earlier in this section. If the tire pressure
is low, the low tire pressure warning light comes on.
SeeTire Pressure Light on page 3-44.
DRIVER DOOR OPEN
This message displays and a chime sounds if the driver
door is not fully closed and the vehicle is in a drive
gear. Stop and turn off the vehicle, check the door for
obstructions, and close the door again. Check to
see if the message still appears on the DIC.
ENGINE HOT A/C (Air Conditioning)
TURNED OFF
This message displays when the engine coolant
becomes hotter than the normal operating temperature.
SeeEngine Coolant Temperature Gage on page 3-43.
To avoid added strain on a hot engine, the air
conditioning compressor automatically turns off. When
the coolant temperature returns to normal, the air
conditioning compressor turns back on. You can
continue to drive your vehicle.
If this message continues to appear, have the system
repaired by your dealer/retailer as soon as possible
to avoid damage to the engine.
ENGINE OVERHEATED IDLE ENGINE
Notice:If you drive your vehicle while the engine
is overheating, severe engine damage may occur.
If an overheat warning appears on the instrument
panel cluster and/or DIC, stop the vehicle as soon
as possible. SeeEngine Overheating on page 5-34
for more information.
This message displays when the engine coolant
temperature is too hot. Stop and allow the vehicle to
idle until it cools down. SeeEngine Coolant
Temperature Gage on page 3-43.
SeeOverheated Engine Protection Operating Mode on
page 5-36for information on driving to a safe place
in an emergency.
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4. With the coolant surge tank pressure cap off, start
the engine and let it run until you can feel the upper
radiator hose getting hot. Watch out for the engine
cooling fan.
By this time, the coolant level inside the coolant
surge tank may be lower. If the level is lower, add
more of the proper mixture to the coolant surge tank
until the level reaches the FULL COLD mark.
5. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
6. Verify coolant level after engine is shut off and the
coolant is cold. If necessary, repeat coolant ll
procedure steps 1 through 6.
Engine Fan Noise
If your vehicle has a clutched engine cooling fan, when
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the fan is spinning slower and the clutch is
not fully engaged. This improves fuel economy and
reduces fan noise. Under heavy vehicle loading, trailer
towing, and/or high outside temperatures, the fan speed
increases as the clutch more fully engages, so you may
hear an increase in fan noise. This is normal and should
not be mistaken as the transmission slipping or making
extra shifts. It is merely the cooling system functioning
properly. The fan will slow down when additional cooling
is not required and the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch partially
disengages.
If your vehicle has electric cooling fans, you may hear
the fans spinning at low speed during most everyday
driving. The fans may turn off if no cooling is required.
Under heavy vehicle loading, trailer towing, and/or
high outside temperatures, or if you are operating
your air conditioning system, the fans may change to
high speed and you may hear an increase in fan noise.
This is normal and indicates that the cooling system
is functioning properly. The fans will change to low
speed when additional cooling is no longer required.
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Tire Terminology and Denitions
Air Pressure:The amount of air inside the
tire pressing outward on each square inch of the
tire. Air pressure is expressed in pounds per
square inch (psi) or kilopascal (kPa).
Accessory Weight
:This means the combined
weight of optional accessories. Some examples of
optional accessories are, automatic transmission,
power steering, power brakes, power windows,
power seats, and air conditioning.
Aspect Ratio
:The relationship of a tire’s height
to its width.
Belt
:A rubber coated layer of cords that is
located between the plies and the tread. Cords
may be made from steel or other reinforcing
materials.
Bead
:The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the rim.
Bias Ply Tire
:A pneumatic tire in which the plies
are laid at alternate angles less than 90 degrees
to the centerline of the tread.Cold Tire Pressure
:The amount of air pressure
in a tire, measured in pounds per square inch (psi)
or kilopascals (kPa) before a tire has built up heat
from driving. SeeInflation - Tire Pressure on
page 5-74.
Curb Weight
:The weight of a motor vehicle with
standard and optional equipment including the
maximum capacity of fuel, oil, and coolant,
but without passengers and cargo.
DOT Markings
:A code molded into the sidewall
of a tire signifying that the tire is in compliance
with the U.S. Department of Transportation (DOT)
motor vehicle safety standards. The DOT code
includes the Tire Identication Number (TIN),
an alphanumeric designator which can also identify
the tire manufacturer, production plant, brand,
and date of production.
GVWR
:Gross Vehicle Weight Rating. See
Loading the Vehicle on page 4-35.
GAWR FRT
:Gross Axle Weight Rating for the
front axle. SeeLoading the Vehicle on page 4-35.
GAWR RR
:Gross Axle Weight Rating for the
rear axle. SeeLoading the Vehicle on page 4-35.
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Fuses Usage
1 Right Trailer Stop/Turn Lamp
2Electronic Stability Suspension
Control, Automatic Level Control
Exhaust
3 Left Trailer Stop/Turn Lamp
4 Engine Controls
Fuses Usage
5Engine Control Module, Throttle
Control
6 Trailer Brake Controller
7 Front Washer
8 Oxygen Sensors
9 Antilock Brakes System 2
10 Trailer Back-up Lamps
11 Driver Side Low-Beam Headlamp
12 Engine Control Module (Battery)
13Fuel Injectors, Ignition Coils
(Right Side)
14Transmission Control Module
(Battery)
15 Vehicle Back-up Lamps
16Passenger Side Low-Beam
Headlamp
17 Air Conditioning Compressor
18 Oxygen Sensors
19 Transmission Controls (Ignition)
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