2008 HUMMER H3 cooling

Dome Lamp Override
E(Dome Lamp Override):You can use the dome
override button, located below the exterior lamps control,
to set the dome and footwell lamps to come on
automatically when a door is opened, or to remain off.
To turn the lamps off, press the button into the in
position. With the button in this position, the dome lamps
will remain off when the doors are open. To return the
lamps to automatic operation, press the button again
and return it to the out position. With the button in this
position, the dome lamps will come on when you
open a door.
Exit Lighting
With exit lighting, the interior lamps will come on when
you remove the key from the ignition. The lamps will not
come on if the dome override button is pressed in.
Reading Lamps
Your vehicle has reading lamps. Press the button
located next to the lamp to turn them on or off.
These lamps will not come on with the dome lamps.
Electric Power Management
The vehicle has Electric Power Management (EPM) that
estimates the battery’s temperature and state of
charge. It then adjusts the voltage for best performance
and extended life of the battery.
When the battery’s state of charge is low, the voltage is
raised slightly to quickly put the charge back in. When
the state of charge is high, the voltage is lowered slightly
to prevent overcharging. If the vehicle has a voltmeter
gage, you may see the voltage move up or down. This is
normal. If there is a problem, an alert will be displayed.
The battery can be discharged at idle if the electrical
loads are very high. This is true for all vehicles. This is
because the generator (alternator) may not be
spinning fast enough at idle to produce all the power
that is needed for very high electrical loads.
A high electrical load occurs when several of the
following loads are on: headlamps, high beams, fog
lamps, rear window defogger, climate control fan at
high speed, heated seats, engine cooling fans, trailer
loads, and loads plugged into accessory power outlets.
Battery Run-Down Protection
This feature shuts off the dome lamp if it is left on for
more than 20 minutes when the ignition is in LOCK. This
will help prevent your battery from running down.
3-20

Ashtray(s) and Cigarette Lighter
Your vehicle may have an ashtray and cigarette lighter.
Your ashtray is located in your center console area.
The ashtray can be removed for cleaning. When
the ashtray is removed, this area can also be used as a
cupholder.
Notice:If you put papers, pins, or other ammable
items in the ashtray, hot cigarettes or other
smoking materials could ignite them and possibly
damage your vehicle. Never put ammable items in
the ashtray.
To use the lighter, press it in all the way, and let go.
When it’s ready, it will pop back out by itself.
Notice:Holding a cigarette lighter in while it is
heating does not let the lighter back away from the
heating element when it is hot. Damage from
overheating can occur to the lighter or heating
element, or a fuse could be blown. Do not hold a
cigarette lighter in while it is heating.
Climate Controls
Climate Control System
The heating, cooling, and ventilation of the vehicle can
be controlled with this system.
Temperature:Turn the left knob on the control panel to
adjust the temperature of the air in the vehicle. Turn
the knob clockwise or counterclockwise to increase or
decrease the temperature.
#(Air Conditioning):Press the center of the left
knob on the control panel to turn the air conditioning
system on or off. An indicator light on the button will be
lit when the air conditioning is turned on. This system
cools and dehumidies the air entering the vehicle.
3-22

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.
3-23

If your vehicle stalls when you are crossing an incline,
be sure you, and any passengers, get out on the
uphill side, even if the door there is harder to open.
If you get out on the downhill side and the vehicle
starts to roll over, you will be right in its path.
If you have to walk down the slope, stay out of the path
the vehicle will take if it does roll over.
Driving in Mud, Sand, Snow, or Ice
When you drive in mud, snow, or sand, your wheels
will not get good traction. You cannot accelerate
as quickly, turning is more difficult, and you will
need longer braking distances.
It is best to use a low gear when you are in mud — the
deeper the mud, the lower the gear. In really deep
mud, the idea is to keep your vehicle moving so you do
not get stuck. Be careful to keep mud from building
up and washing onto the engine cooling system.
When you drive on sand, you will sense a change in
wheel traction. But it will depend upon how loosely
packed the sand is. On loosely packed sand, such
as on beaches or sand dunes, your tires will tend
to sink into the sand. This has an effect on steering,
accelerating, and braking. Drive at a reduced speed
and avoid sharp turns or abrupt maneuvers.
4-29

If the water is not too deep, drive slowly through it.
At faster speeds, water splashes on your ignition system
and your vehicle can stall. Stalling can also occur if
you get your tailpipe under water. And, as long as
your tailpipe is under water, you will never be able
to start your engine. When you go through water,
remember that when your brakes get wet, it may
take you longer to stop.
SeeDriving in Rain and on Wet Roads on page 4-33for
more information on driving through water.
After Off-Road Driving
Remove any brush or debris that has collected on
the underbody, chassis, or under the hood. These
accumulations can be a re hazard.
After operation in mud or sand, have the brake linings
cleaned and checked. These substances can cause
glazing and uneven braking. Check the engine and
oil coolers and underbody skid shields for mud
accumulation. Thoroughly and carefully clean these
devices to allow proper cooling. Check the bodystructure, steering, suspension, underbody shields,
wheels, tires, and exhaust system for damage. Also,
check the fuel lines and cooling system for any leakage.
Your vehicle will require more frequent service due
to off-road use. See the Maintenance Schedule
for additional information.
Assist Steps
If your vehicle has removable side steps, remove the
steps prior to off-roading to give your vehicle more ground
clearance and to prevent damage to the vehicle from the
side steps dragging and/or catching on obstacles.
Notice:Do not drive off-road with the side steps
attached to your vehicle. You can damage the
side steps and/or your vehicle’s frame if they get
caught or drag against an obstacle. This damage
would not be covered by your vehicle’s warranty.
Always remove the side steps prior to any off-road
driving.
4-31

Before Leaving on a Long Trip
To prepare your vehicle for a long trip, consider having
it serviced by your dealer/retailer before departing.
Things to check on your own include:
Windshield Washer Fluid:Reservoir full? Windows
clean — inside and outside?
Wiper Blades:In good shape?
Fuel, Engine Oil, Other Fluids:All levels checked?
Lamps:Do they all work and are lenses clean?
Tires:Are treads good? Are tires inated to
recommended pressure?
Weather and Maps:Safe to travel? Have up-to-date
maps?
Highway Hypnosis
Always be alert and pay attention to your surroundings
while driving. If you become tired or sleepy, nd a
safe place to park your vehicle and rest.
Other driving tips include:
Keep the vehicle well ventilated.
Keep interior temperature cool.
Keep your eyes moving — scan the road ahead
and to the sides.
Check the rearview mirror and vehicle instruments
often.
Hill and Mountain Roads
Driving on steep hills or through mountains is different
than driving on at or rolling terrain. Tips for driving
in these conditions include:
Keep your vehicle serviced and in good shape.
Check all uid levels and brakes, tires, cooling
system, and transmission.
Going down steep or long hills, shift to a
lower gear.
4-34

When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
start your engine,
shift into a gear, and
release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you’re
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission uid, engine
oil, axle lubricant, belts, cooling system and brake
system. Each of these is covered in this manual, and
the Index will help you nd them quickly. If you’re
trailering, it’s a good idea to review these sections
before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Trailer Wiring Harness
Light-Duty Trailer Wiring Package
If your vehicle is not equipped with a trailer towing
package, the chassis harness will contain the following
blunt cut circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
White: Ground
Brown: Tail Lamps
If you want to add on a trailer tow, it should be installed
by your dealer/retailer or a qualied service center.
Also, seeAdd-On Electrical Equipment on page 5-101
for more information.
4-59

Service............................................................5-3
Accessories and Modications..........................5-3
California Proposition 65 Warning.....................5-4
California Perchlorate Materials Requirements.....5-4
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of
Your Vehicle..............................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specications....................................5-5
California Fuel...............................................5-6
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-7
Filling the Tank..............................................5-8
Filling a Portable Fuel Container.....................5-10
Checking Things Under the Hood....................5-11
Hood Release..............................................5-11
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-15
Engine Oil Life System..................................5-18
Engine Air Cleaner/Filter................................5-20
Automatic Transmission Fluid.........................5-21
Manual Transmission Fluid.............................5-24
Hydraulic Clutch...........................................5-26Engine Coolant.............................................5-27
Radiator Pressure Cap..................................5-29
Engine Overheating.......................................5-29
Cooling System............................................5-31
Engine Fan Noise.........................................5-36
Power Steering Fluid.....................................5-36
Windshield Washer Fluid................................5-37
Brakes........................................................5-38
Battery........................................................5-41
Jump Starting...............................................5-42
Rear Axle
.......................................................5-45
Four-Wheel Drive............................................5-46
Front Axle......................................................5-46
Headlamp Aiming...........................................5-46
Bulb Replacement..........................................5-49
Halogen Bulbs..............................................5-49
Headlamps..................................................5-49
Taillamps, Turn Signal, Stoplamps and
Back-up Lamps.........................................5-50
License Plate Lamp......................................5-51
Replacement Bulbs.......................................5-52
Windshield Wiper Blade Replacement..............5-52
Section 5 Service and Appearance Care
5-1