2008 HUMMER H3 engine

The air conditioning will not function if the fan is turned
off. If air conditioning is selected with fan off, the
indicator light ashes three times and then turns off.
A slight change in engine performance may occur when
the air conditioning compressor shuts off and turns
on again. This is normal. The system is designed
to make adjustments to help with fuel economy while
still maintaining the selected temperature.
The air conditioning system removes moisture from the
air, so sometimes there may be a small amount of
water dripping underneath the vehicle while idling or
after turning off the engine. This is normal.
9(Fan):Turn the center knob on the control panel to
control the fan speed. Turn the knob clockwise or
counterclockwise to increase or decrease the fan speed.
9(Off):Turn the center knob to this position to turn
the fan off. With the fan off, you may still experience
airow from the system that increases with vehicle
speed depending on the mode and temperature settings.
Enable recirculation mode to stop this airow from
occurring.
@(Recirculation):Press the center of the fan
control knob to recirculate air inside the vehicle and
prevent outside air from coming in. It can be used
to prevent outside odors from entering the vehicle and
cool the air inside the vehicle more quickly. Pressthis button to turn the recirculation mode on or off. An
indicator light on the button comes on to show that
the recirculation mode is activated.
Recirculation is available in the bi-level, and vent
modes. Recirculation is not available while in oor,
oor/defog and defrost mode. If recirculation is selected
in these modes, the indicator ashes three times
indicating it is not available in that mode. When the
recirculation mode is turned on, the air conditioning turns
on automatically.
When it is hot enough outside, the recirculation mode
may turn on automatically to help improve cooling
performance. The indicator light will be lit to show this
mode is active. If the recirculation button is pressed
while in this mode, the light will ash three times
and stay on to indicate that recirculation may not be
shut off.
The right knob on the control panel is used to direct the
airow inside the vehicle. In-between modes are
available by moving the right control knob between
modes with symbols. The in-between mode is a
combination of the two modes that the control is
centered between.
Turn the right knob to select one of the following modes:
H(Vent):This mode directs air to the instrument
panel outlets.
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Move the louvers up or down to change the direction of
the airow. Use the thumbwheel under the outlets to
change the direction of the airow from left to right.
Operation Tips

Enable recirculation mode for maximum air
conditioning performance.
Clear away any ice, snow or leaves from the air
inlets at the base of the windshield that may
block the ow of air into your vehicle.
Use of non-GM approved hood deectors may
adversely affect the performance of the system.
Keep the path under the front seats clear of objects
to help circulate the air inside of your vehicle more
effectively.
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 may also have a Driver Information Center
(DIC) that works along with the warning lights and gages.
SeeDriver Information Center (DIC) on page 3-40for
more information.
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Speedometer and Odometer
The speedometer lets you see your speed in both miles
per hour (mph) and kilometers per hour (km/h).
The odometer shows how far your vehicle has been
driven, in either miles (used in the United States)
or kilometers (used in Canada).
The odometer mileage can be checked without the
vehicle running by pressing the trip information stem.
See “Odometer” underDIC Operation and Displays
on page 3-40for more information.
If the cluster is replaced the new one will automatically
detect and update the vehicle’s accumulated mileage.
Trip Odometer
Your vehicle has a trip odometer that can tell you how
far your vehicle has been driven since you last set
the trip odometer to zero.
See “Trip Odometer” underDIC Operation and Displays
on page 3-40for more information.
Tachometer
The tachometer
displays the engine
speed in revolutions
per minute (rpm).
Notice:If you operate the engine with the
tachometer in the shaded warning area, your vehicle
could be damaged, and the damages would not
be covered by your warranty. Do not operate
the engine with the tachometer in the shaded
warning area.3.7L L5 Shown,
5.3L V8 Similar
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Safety Belt Reminders
Safety Belt Reminder Light
When the engine is started, a chime will come on for
several seconds to remind people to fasten their safety
belts, unless the driver’s safety belt is already buckled.
The safety belt light will
also come on and stay
on for several seconds,
then it will ash for
several more.
This chime and light is repeated if the driver remains
unbuckled and the vehicle is in motion. If the driver’s belt
is already buckled, neither the chime nor the light will
come on.
Passenger Safety Belt Reminder Light
Several seconds after the engine is started, a chime
will sound for several seconds to remind the front
passenger to buckle their safety belt. This would only
occur if the passenger airbag is enabled. SeePassenger
Sensing System on page 1-62for more information.
The passenger safety belt light, located on the
instrument panel, will come on and stay on for
several seconds and then ash for several more.
This chime and light are
repeated if the passenger
remains unbuckled and
the vehicle is in motion.
If the passenger’s safety belt is buckled, neither the
chime nor the light will come on.
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Airbag Readiness Light
There is an airbag readiness light on the instrument
panel cluster, which shows the airbag symbol. The
system checks the airbag’s electrical system for
malfunctions. The light tells you if there is an electrical
problem. The system check includes the airbag
sensor, the pretensioners, the airbag modules, the
wiring and the crash sensing and diagnostic module.
For more information on the airbag system, seeAirbag
System on page 1-54.
This light will come on
when you start your
vehicle, and it will ash
for a few seconds.
The light should go out
and the system is ready.
If the airbag readiness light stays on after you start
the vehicle or comes on when you are driving,
your airbag system may not work properly. Have
your vehicle serviced right away.{CAUTION:
If the airbag readiness light stays on after you
start your vehicle, it means the airbag system
may not be working properly. The airbags in
your vehicle may not inate in a crash, or they
could even inate without a crash. To help
avoid injury to yourself or others, have your
vehicle serviced right away if the airbag
readiness light stays on after you start your
vehicle.
The airbag readiness light should ash for a few
seconds when you start the engine. If the light does not
come on then, have it xed immediately. If there is a
problem with the airbag system, an airbag Driver
Information Center (DIC) message may also come on.
SeeDIC Warnings and Messages on page 3-43for
more information.
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Charging System Light
This light will come on
briey when you turn on
the ignition, but the engine
is not running, as a
check to show you it
is working.
It should go out once the engine is running. If it stays
on, or comes on while you are driving, you may have a
problem with the charging system. A charging system
Driver Information Center (DIC) message may also
appear. SeeDIC Warnings and Messages on page 3-43
for more information. This light could indicate that you
have problems with a generator drive belt, or another
electrical problem. Have it checked right away. If
you must drive a short distance with the light on, be
certain to turn off all your accessories, such as the radio
and air conditioner.
Up-Shift Light
Your vehicle may have an
up-shift light.
When this light comes on, you should shift to the next
higher gear if weather, road, and traffic conditions allow
you to.
SeeManual Transmission Operation on page 2-26for
more information.
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Antilock Brake System Warning
Light
For vehicles with the
Antilock Brake System
(ABS), this light will come
on briey when you
start the engine.
That is normal. If the light does not come on then, have it
xed so it will be ready to warn you if there is a problem.
If the ABS light stays on, turn the ignition off, if the light
comes on when you are driving, stop as soon as it
is safely possible and turn the ignition off. Then start the
engine again to reset the system. If the ABS light still
stays on, or comes on again while you are driving, your
vehicle needs service. If the regular brake system
warning light is not on, you still have brakes, but you do
not have antilock brakes. If the regular brake system
warning light is also on, you do not have antilock brakes
and there is a problem with your regular brakes. See
Brake System Warning Light on page 3-33
For vehicles with a Driver Information Center (DIC), see
DIC Warnings and Messages on page 3-43for all
brake related DIC messages.
Traction Off Light
If you have the Traction
Control System (TCS), this
light will come on when the
TCS has been turned off.
This light will come on briey when the ignition is turned
to ON, if it does not the system may require service.
For more information on the traction off light, see
Traction Control System (TCS) on page 4-5.
StabiliTrak®Not Ready Light
If you have the StabiliTrak®
system, this light will come
on when the StabiliTrak®
system has been
turned off.
This light will come on briey when the ignition is turned
to ON, if it does not the system may require service.
For more information, seeStabiliTrak
®System on
page 4-7.
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Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.
If the gage pointer is in the shaded area of the gage,
the engine is too hot. It means that your engine coolant
has overheated. If you have been operating your
vehicle under normal driving conditions, you should pull
off the road, stop your vehicle and turn off the engine
as soon as possible.
SeeEngine Overheating on page 5-29for more
information.
Tire Pressure Light
This light comes on briey
when the engine is started.
This light will also come on when one or more of your
tires are signicantly underinated.
A tire pressure message in the Driver Information
Center (DIC), may accompany the light. SeeDIC
Warnings and Messages on page 3-43for more
information.
Stop and check your tires as soon as it is safe to do so.
If underinated, inate to the proper pressure. See
Tires on page 5-54for more information.
If a problem is detected with the Tire Pressure Monitor
System, this light will ash for approximately
60 seconds and then stay on solid for the remainder of
the ignition cycle. SeeTire Pressure Monitor System
on page 5-63for more information. United States
Canada
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