brakes HUMMER H3 2010 User Guide

9-18 Driving and Operating
Driving Downhill
When off-roading takes you
downhill, consider:
.How steep is the downhill?
Will I be able to maintain vehicle
control?
.What is the surface like?
Smooth? Rough? Slippery?
Hard-packed dirt? Gravel?
.Are there hidden surface
obstacles? Ruts? Logs?
Boulders?
.What is at the bottom of the hill?
Is there a hidden creek bank or
even a river bottom with large
rocks?
If you decide you can go down
a hill safely, try to keep the vehicle
headed straight down. Use a low
gear so engine drag can help the
brakes so they do not have to do all
the work. Descend slowly, keeping
the vehicle under control at all
times.
{WARNING
Heavy braking when going down
a hill can cause your brakes to
overheat and fade. This could
cause loss of control and a
serious accident. Apply the
brakes lightly when descending a
hill and use a low gear to keep
vehicle speed under control.
Things not to do when driving down
a hill:
.When driving downhill, avoid
turns that take you across the
incline of the hill. A hill that is not
too steep to drive down might be
too steep to drive across. The
vehicle could roll over.
.Never go downhill with the
transmission in N (Neutral),
called free-wheeling. The brakes
will have to do all the work and
could overheat and fade. Vehicles are much more likely to
stall when going uphill, but if it
happens when going downhill:
1. Stop the vehicle by applying the
regular brakes and apply the
parking brake.
2. With an automatic transmission, shift to P (Park). While still
braking, restart the engine.
3. Shift back to a low gear, release the parking brake, and drive
straight down.
4. If the engine will not start, get out and get help.

Driving and Operating 9-21
Driving in Water
{WARNING
Driving through rushing water can
be dangerous. Deep water can
sweep your vehicle downstream
and you and your passengers
could drown. If it is only shallow
water, it can still wash away the
ground from under your tires, and
you could lose traction and roll
the vehicle over. Do not drive
through rushing water.
Heavy rain can mean flash flooding,
and flood waters demand extreme
caution. Find out how deep the water is
before driving through it. Do not
try it if it is deep enough to cover
the wheel hubs, axles, or exhaust
pipe
—you probably will not get
through. Deep water can damage
the axle and other vehicle parts.
The vehicle is capable of depths up
to 50 cm (20 inches). Know how to
judge whether the water is deeper
than this before proceeding into it.
If the water is not too deep, drive
slowly through it. At faster speeds,
water splashes on the ignition
system and the vehicle can stall.
Stalling can also occur if you get the
tailpipe under water. If the tailpipe is
under water, you will never be able
to start the engine. When going
through water, remember that when
the brakes get wet, it might take
longer to stop. See Driving on Wet
Roads on page 9‑22.
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 fire 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
for mud accumulation. Thoroughly
and carefully clean these devices
to allow proper cooling. Check
the body structure, steering,
suspension, wheels, tires, and
exhaust system for damage and
check the fuel lines and cooling
system for any leakage.
The vehicle requires more frequent
service due to off-road use. Refer
to the Maintenance Schedule for
additional information.

9-22 Driving and Operating
Driving on Wet Roads
Rain and wet roads can reduce
vehicle traction and affect your
ability to stop and accelerate.
Always drive slower in these types
of driving conditions and avoid
driving through large puddles and
deep‐standing or flowing water.
{WARNING
Wet brakes can cause crashes.
They might not work as well in
a quick stop and could cause
pulling to one side. You could
lose control of the vehicle.
After driving through a large
puddle of water or a car/vehicle
wash, lightly apply the brake
pedal until the brakes work
normally.(Continued)
WARNING (Continued)
Flowing or rushing water creates
strong forces. Driving through
flowing water could cause your
vehicle to be carried away. If this
happens, you and other vehicle
occupants could drown. Do not
ignore police warnings and be
very cautious about trying to drive
through flowing water.
Hydroplaning
Hydroplaning is dangerous. Water
can build up under your vehicle's
tires so they actually ride on the
water. This can happen if the road
is wet enough and you are going
fast enough. When your vehicle is
hydroplaning, it has little or no
contact with the road.
There is no hard and fast rule about
hydroplaning. The best advice is to
slow down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet
weather driving tips include:
.Allow extra following distance.
.Pass with caution.
.Keep windshield wiping
equipment in good shape.
.Keep the windshield washer fluid
reservoir filled.
.Have good tires with proper
tread depth. SeeTireson
page 10‑44.
.Turn off cruise control.
Highway Hypnosis
Always be alert and pay attention
to your surroundings while driving.
If you become tired or sleepy, find a
safe place to park your vehicle
and rest.

Driving and Operating 9-23
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 flat or rolling terrain. Tips for
driving in these conditions include:
.Keep the vehicle serviced and in
good shape.
.Check all fluid levels and brakes,
tires, cooling system, and
transmission.
.Going down steep or long hills,
shift to a lower gear.
{WARNING
If you do not shift down, the
brakes could get so hot that they
would not work well. You would
then have poor braking or even
none going down a hill. You could
crash. Shift down to let the engine
assist the brakes on a steep
downhill slope.
{WARNING
Coasting downhill in N (Neutral)
or with the ignition off is
dangerous. The brakes will have
to do all the work of slowing down
and they could get so hot that
they would not work well. You
would then have poor braking or
even none going down a hill. You
could crash. Always have the
engine running and the vehicle in
gear when going downhill.
.Stay in your own lane. Do not
swing wide or cut across the
center of the road. Drive at
speeds that let you stay in your
own lane.
.Top of hills: Be alert —
something could be in your
lane (stalled car, accident).
.Pay attention to special road
signs (falling rocks area, winding
roads, long grades, passing or
no-passing zones) and take
appropriate action.

9-24 Driving and Operating
Winter Driving
Driving on Snow or Ice
Drive carefully when there is snow
or ice between the tires and the
road, creating less traction or grip.
Wet ice can occur at about 0°C
(32°F) when freezing rain begins to
fall, resulting in even less traction.
Avoid driving on wet ice or in
freezing rain until roads can be
treated with salt or sand.
Drive with caution, whatever the
condition. Accelerate gently so
traction is not lost. Accelerating too
quickly causes the wheels to spin
and makes the surface under the
tires slick, so there is even less
traction.
Try not to break the fragile traction.
If you accelerate too fast, the drive
wheels will spin and polish the
surface under the tires even more.The
Antilock Brake System (ABS)
on page 9‑50improves vehicle
stability during hard stops on
slippery roads, but apply the brakes
sooner than when on dry pavement.
Allow greater following distance on
any slippery road and watch for
slippery spots. Icy patches can
occur on otherwise clear roads in
shaded areas. The surface of a
curve or an overpass can remain icy
when the surrounding roads are
clear. Avoid sudden steering
maneuvers and braking while
on ice.
Turn off cruise control, if equipped,
on slippery surfaces.Blizzard Conditions
Being stuck in snow can be a
serious situation. Stay with the
vehicle unless there is help nearby.
If possible, use the Roadside
Service
on page 13‑5. To get help
and keep everyone in the
vehicle safe:
.Turn on the hazard warning
flashers.
.Tie a red cloth to an outside
mirror.
{WARNING
Snow can trap engine exhaust
under the vehicle. This may
cause exhaust gases to get
inside. Engine exhaust contains
carbon monoxide (CO) which
cannot be seen or smelled. It can
cause unconsciousness and even
death.
(Continued)

9-42 Driving and Operating
It features an electronic shift
position indicator within the
instrument cluster.
There are several different positions
for the shift lever.
P (Park):This position locks the
rear wheels. It is the best position
to use when you start the engine
because the vehicle cannot move
easily.
{WARNING
It is dangerous to get out of the
vehicle if the shift lever is not fully
in P (Park) with the parking brake
firmly set. The vehicle can roll.
Do not leave the vehicle when
the engine is running unless you
have to. If you have left the
engine running, the vehicle can
move suddenly. You or others
could be injured. To be sure the
vehicle will not move, even when
you are on fairly level ground,
always set the parking brake and
move the shift lever to P (Park).
See Shifting Into Park
on
page 9‑37
. If you are pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑70. Make sure the shift lever is fully in
P (Park) before starting the engine.
The vehicle has an automatic
transmission shift lock control
system. You must fully apply the
regular brakes first and then press
the shift lever button before you can
shift from P (Park) when the ignition
key is in ON/RUN. If you cannot
shift out of P (Park), ease pressure
on the shift lever and push the shift
lever all the way into P (Park) as
you maintain brake application.
Then press the shift lever button
and move the shift lever into
another gear. See
Shifting Out of
Park on page 9‑38.
R (Reverse): Use this gear to
back up.
Notice: Shifting to R (Reverse)
while the vehicle is moving
forward could damage the
transmission. The repairs would
not be covered by the vehicle
warranty. Shift to R (Reverse) only
after the vehicle is stopped.

Driving and Operating 9-43
To rock the vehicle back and forth to
get out of snow, ice, or sand without
damaging the transmission, see
If the Vehicle is Stuck on page 9‑26.
N (Neutral):In this position, the
engine does not connect with the
wheels. To restart the engine when
the vehicle is already moving, use
N (Neutral) only.
{WARNING
Shifting into a drive gear while the
engine is running at high speed is
dangerous. Unless your foot is
firmly on the brake pedal, the
vehicle could move very rapidly.
You could lose control and hit
people or objects. Do not shift
into a drive gear while the engine
is running at high speed. Notice:
Shifting out of P (Park)
or N (Neutral) with the engine
running at high speed may
damage the transmission. The
repairs would not be covered by
the vehicle warranty. Be sure the
engine is not running at high
speed when shifting the vehicle.
D (Drive): This position is for
normal driving. It provides the best
fuel economy. If you need more
power for passing, and you are:.Going less than about 55 km/h
(35 mph), push the accelerator
pedal about halfway down.
.Going about 55 km/h (35 mph) or
more, push the accelerator all
the way down. Downshifting the transmission in
slippery road conditions could result
in skidding, see
“Skidding”under
Loss of Control on page 9‑6.
D (Drive) can be used when towing
a trailer. You may want to shift
the transmission to 3 (Third) or,
if necessary, a lower gear if the
transmission shifts too often under
heavy loads or in hilly conditions.
3 (Third): This position is also
used for normal driving. However it
reduces vehicle speed more than
D (Drive) without using the brakes.
You might choose 3 (Third) instead
of D (Drive) when driving on hilly or
winding roads, or when towing a
trailer, so there is less shifting
between gears, or when going down
a steep hill.

9-44 Driving and Operating
2 (Second):This position reduces
vehicle speed even more than
3 (Third) without using the brakes.
You can use 2 (Second) on hills.
It can help control vehicle speed as
you go down steep mountain roads,
but then you would also want to use
the brakes off and on.
1 (First): This position reduces
vehicle speed even more than
2 (Second) without using the brakes.
You can use it on very steep hills,
or in deep snow or mud. If the shift
lever is put in 1 (First) while the
vehicle is moving forward, the
transmission will not shift into
first gear until the vehicle is going
slowly enough. Notice:
Spinning the tires
or holding the vehicle in
one place on a hill using only
the accelerator pedal may
damage the transmission.
The repair will not be covered by
the vehicle warranty. If you are
stuck, do not spin the tires. When
stopping on a hill, use the brakes
to hold the vehicle in place.
Hill Start Assist
H3 and H3T vehicles have a Hill
Start Assist feature, which may be
useful when stopped on a grade.
See Braking
on page 9‑3for more
information.
Manual Transmission
This is the shift pattern.
Vehicles with a manual transmission
operate as described below:
1 (First): Press the clutch pedal
and shift into 1 (First). Then slowly
let up on the clutch pedal as
you slowly press down on the
accelerator pedal.

9-50 Driving and Operating
Brakes
Antilock Brake
System (ABS)
This vehicle has the Antilock Brake
System (ABS), an advanced
electronic braking system that helps
prevent a braking skid.
When the engine is started and the
vehicle begins to drive away, ABS
checks itself. A momentary motor or
clicking noise might be heard while
this test is going on, and it might
even be noticed that the brake
pedal moves a little. This is normal.
If there is a problem with ABS, this
warning light stays on. SeeAntilock
Brake System (ABS) Warning Light
on page 5‑15. If driving safely on a wet road and
it becomes necessary to slam on
the brakes and continue braking
to avoid a sudden obstacle, a
computer senses that the wheels
are slowing down. If one of the
wheels is about to stop rolling, the
computer will separately work the
brakes at each wheel.
ABS can change the brake pressure
to each wheel, as required, faster
than any driver could. This can help
the driver steer around the obstacle
while braking hard.
As the brakes are applied, the
computer keeps receiving updates
on wheel speed and controls
braking pressure accordingly.
Remember: ABS does not change
the time needed to get a foot up to
the brake pedal or always decrease
stopping distance. If you get too
close to the vehicle in front of you,
there will not be enough time to
apply the brakes if that vehicle
suddenly slows or stops. Always
leave enough room up ahead to
stop, even with ABS.
Using ABS
Do not pump the brakes. Just hold
the brake pedal down firmly and let
ABS work. The ABS pump or motor
might be heard operating, and the
brake pedal might be felt to pulsate,
but this is normal.
Braking in Emergencies
ABS allows the driver to steer and
brake at the same time. In many
emergencies, steering can help
more than even the very best
braking.

9-52 Driving and Operating
The stability system hydraulic brake
control module increases brake
pressure at each corner of the
vehicle until the ABS activates.
Minor brake pedal pulsations or
pedal movement during this time
is normal and the driver should
continue to apply the brake pedal
as the driving situation dictates.
The brake assist feature will
automatically disengage when
the brake pedal is released or
brake pedal pressure is quickly
decreased.
Hill Start Assist (HSA)
This vehicle has a Hill Start Assist
(HSA) feature, which may be useful
when the vehicle is stopped on a
grade. This feature is designed to
prevent the vehicle from rolling,
either forward or rearward, during
vehicle drive off. After the vehicle
is stopped on an incline, quickly
push the brake pedal to the floor
to activate Hill Start Assist.When the system activates, a
chime will sound and the HSA ON
message will be displayed. The
brakes will automatically be held
for a maximum of two seconds
while the driver switches from
applying the brakes to pushing
the accelerator pedal. When Hill
Start Assist is active, the driver
might experience a
“hard brake
pedal.” This is normal and does
not affect safe brake operation.
After activation, the system will
automatically disengage when the
accelerator pedal is pressed. Do
not turn off the ignition while this
feature is active. The Hill Start
Assist feature may not disengage
fully if the ignition is turned off.
The system will not activate with
the transmission in P (Park), when
traveling down a steep grade in a
drive gear, or if the vehicle is facing
uphill with the transmission in
R (Reverse).
Ride Control Systems
Traction Control
System (TCS)
The vehicle has a Traction Control
System (TCS) that limits wheel
spin. This is especially useful in
slippery road conditions. The
system operates only if it senses
that any of the wheels are spinning
or beginning to lose traction. When
this happens, TCS reduces engine
power. The system may be heard
or felt while it is working. This is
normal and does not mean there is
a problem with the vehicle.
TCS can operate on dry roads
under some conditions. When
this happens, the system may be
heard working or a reduction in
acceleration may be noticed. This
is normal and does not mean there
is a problem with the vehicle.