2007 GMC SIERRA Owner's Manual

Pressing one of these buttons when the system is
off will turn the system on. Pressing one of
these buttons when in automatic control will place
the fan under manual control. The fan setting
will remain displayed and the AUTO light will turn
off. The air delivery mode will remain under
automatic control.
yNz(Mode):Press the mode up and down
buttons to manually change the direction of
the airow in your vehicle. Repeatedly press the
button until the desired mode appears on the
display. Pressing one of these buttons when the
system is off will change air delivery mode without
turning the system on. Pressing one of these
buttons when in automatic control will place the
mode under manual control.
The air delivery mode setting will be displayed and
the AUTO light will turn off. The fan will remain
under automatic control.
H(Vent):Air is directed to the instrument
panel outlets.
)(Bi-Level):Air is directed partly to the
instrument panel outlets and to the oor outlets. A
little air is directed towards the windshield and
side window outlets. Cooler air is directed to the
upper outlets and warmer air to the oor outlets.
6(Floor):Air is directed to the oor outlets, with
some to the windshield, side window outlets,
and second row oor outlets. In this mode, the
system will automatically select outside air.
-(Defog):See “Defogging and Defrosting” later
in this section.
@(Recirculation):Press this button to turn the
recirculation mode on. When the button is
pressed, an indicator light will come on.
This mode keeps outside air from entering the
vehicle. It can be used to reduce outside air and
prevent odors from entering the vehicle.
Recirculation may also help cool the air inside the
vehicle more quickly once the temperature inside
the vehicle is less than the outside temperature.
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The recirculation mode cannot be used with oor,
defog, or defrost modes. If recirculation is selected
with one of those modes, the indicator light will ash
three times and then turn off. 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 defog or defrost
mode and increase the fan speed.
The recirculation mode can be turned off by
pressing the outside air button, or by turning off
the ignition.
;(Outside Air):Press this button to turn on
the outside air mode. When this mode is selected,
air from outside the vehicle will circulate
throughout your vehicle. An indicator light on the
button will come on to let you know that it is
activated. The outside air mode can be used
with all modes, but it cannot be used with
the recirculation mode.
Air Conditioning
#
(Air Conditioning):Press this button to turn
the air conditioning (A/C) compressor on and
off. When air conditioning is selected, an indicator
light comes on to let you know that the air
conditioning has been activated.
Pressing this button when the outside temperature
is too cool for air conditioning makes the air
conditioning indicator 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 air conditioning light turns
off to let you know the air conditioning mode has
been canceled.
On hot days, open the windows long enough to let
hot inside air escape. This helps to reduce the
time it takes for the vehicle to cool down. It also
helps the system to operate more efficiently.
The air conditioning system removes moisture from
the air, so you might notice a small amount of
water dripping underneath the vehicle while idling
or after turning off the engine. This is normal.
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Sensors
The solar sensor, located in the defrost grille,
middle of the instrument panel, monitors the solar
radiation. Do not cover the solar sensor or the
system will not work properly.The interior temperature sensor, located in the
headliner, measures the temperature of the
air inside your 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 on the rearview mirror.
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.
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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
clear fog or frost from the windshield.
Use the mode up and down arrows to select the
defog or defrost modes.
-(Defog):Press this button 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 your 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.
Rear Window Defogger
The rear window defogger uses a warming grid to
remove fog from the rear window.
<(Rear Window Defogger):If your vehicle
has this feature, press this button to turn the
defogger on or off. It will automatically turn
off several minutes after it has been activated.
The defogger can also be turned off by turning the
engine off. Do not drive the vehicle until all the
windows are clear.
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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.
W(Heated Mirrors):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. SeeOutside Power Mirrors on page 176.
Outlet Adjustment
Use the air outlets located in the center and on
the side of the 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
better, reducing the chance of fogging
the inside of your windows.
When you enter a vehicle in cold weather, set
the fan speed to maximum airow 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.
Adding outside equipment to the front of the
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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Warning Lights, Gages, and
Indicators
This part describes the warning lights and gages on
your vehicle. The pictures help to locate them.
Warning lights and gages can signal that something
is wrong before it becomes serious enough to
cause an expensive repair or replacement. Paying
attention to the warning lights and gages could also
save you or others from injury.
Warning lights come on when there may be or is a
problem with one of your vehicle’s functions. As
the details show on the next few pages, some
warning lights come on briey when you start the
engine just to let you know they are working. If
you are familiar with this section, you should
not be alarmed when this happens.Gages can indicate when there may be or is a
problem with one of your vehicle’s functions. Often
gages and warning lights work together to let
you know when there is a problem with your
vehicle.
When one of the warning lights comes on and
stays on as you are driving, or when one of
the gages shows there may be a problem, check
the section that tells you what to do about it.
Please follow this manual’s advice. Waiting to do
repairs can be costly and even dangerous. So
please get to know your vehicle’s warning
lights and gages. They can be a big help.
Your vehicle also has a Driver Information
Center (DIC) that works along with warning lights
and gages. SeeDIC Warnings and Messages
on page 279for more information.
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Instrument Panel Cluster
Your instrument cluster is designed to let you know at a glance how your vehicle is running. You will
know how fast you are going, about how much fuel you have and many other things you will need to know
to drive safely and economically. If your vehicle has the DURAMAX
®Diesel engine, see the DURAMAX®
Diesel manual for more information.
United States Light Duty Premium version shown. Canada, Uplevel, Base, Heavy Duty Clusters similar.
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Speedometer and Odometer
Your speedometer lets you see your speed in both
miles per hour (mph) and kilometers per hour
(km/h). Your odometer shows how far your vehicle
has been driven, in either miles (used in the United
States) or kilometers (used in Canada).
Engine Hour Meter Display
The Driver Information Center (DIC) can also
display the number of hours the engine has run.
To display the engine hours, turn the ignition
off, press and hold the reset button for at least
four seconds. The hour meter will be displayed for
up to 30 seconds, or until the ignition is turned
on. SeeDIC Operation and Displays (With
DIC Buttons) on page 268orDIC Operation and
Displays (Without DIC Buttons) on page 275
for more information.
Trip Odometer
The trip odometer can tell you how far your
vehicle has been driven since you last set the trip
odometer to zero.
Press the reset button, located on the instrument
panel cluster next to the voltmeter, to toggle
between the trip odometer and the regular
odometer. Holding the reset button for
approximately one second while the trip odometer
is displayed will reset it.
To display the odometer reading with the ignition
off, press the reset button.
SeeDIC Operation and Displays (With DIC
Buttons) on page 268orDIC Operation and
Displays (Without DIC Buttons) on page 275for
more information.
Tachometer
Your tachometer displays the engine speed in
revolutions per minute (rpm). See “Grade Braking
(Allison Transmission
®)” underTow/Haul Mode
on page 144for more information.
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