wheel HUMMER H3 2010 Service Manual

9-34 Driving and Operating
Ignition Positions
The ignition switch has four different
positions.
To shift out of P (Park), turn the
ignition to ON/RUN and apply the
regular brake pedal.
Notice:Using a tool to force the
key to turn in the ignition could
cause damage to the switch or
break the key. Use the correct
key, make sure it is all the way in,
and turn it only with your hand.
If the key cannot be turned by
hand, see your dealer. (A) LOCK/OFF:
This position
locks the ignition. It also locks
the transmission on automatic
transmission vehicles. It locks
the steering wheel on manual
transmission vehicles. The key can
only be removed in LOCK/OFF.
On vehicles with an automatic
transmission, the shift lever must be
in P (Park) to turn the ignition switch
to LOCK/OFF.
The steering can bind with the
wheels turned off center. If this
happens, move the steering wheel
from right to left while turning the
key to ACC/ACCESSORY. If this
doesn't work, then the vehicle needs
service.
(B) ACC/ACCESSORY: This is the
position in which you can operate
the electrical accessories or items
plugged into the accessory power
outlets. On automatic transmission
vehicles, this position unlocks the
ignition. On manual transmission
vehicles, it unlocks the ignition and steering wheel. Use this position
if the vehicle must be pushed or
towed.
(C) ON/RUN:
This position can
be used to operate the electrical
accessories and to display some
instrument panel cluster warning
and indicator lights. The switch
stays in this position when the
engine is running. The transmission
is also unlocked in this position on
automatic transmission vehicles.
If you leave the key in the
ACC/ACCESSORY or ON/RUN
position with the engine off, the
battery could be drained. You may
not be able to start the vehicle if the
battery is allowed to drain for an
extended period of time.
(D) START: This is the position that
starts the engine. When the engine
starts, release the key. The ignition
switch returns to ON/RUN for
driving.

Driving and Operating 9-37
3. Plug it into a normal, grounded110-volt AC outlet.
{WARNING
Plugging the cord into an
ungrounded outlet could cause an
electrical shock. Also, the wrong
kind of extension cord could
overheat and cause a fire. You
could be seriously injured. Plug
the cord into a properly grounded
three-prong 110-volt AC outlet.
If the cord will not reach, use a
heavy-duty three-prong extension
cord rated for at least 15 amps.
4. Before starting the engine, be sure to unplug and store the
cord to prevent damage.
The length of time the heater should
remain plugged in depends on
several factors. Ask a dealer in the
area where you will be parking the
vehicle for the best advice on this.
Shifting Into Park
{WARNING
It can be 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. 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, use the steps
that follow. If you are pulling a
trailer, see Driving Characteristics
and Towing Tips on page 9‑70.
1. Hold the brake pedal down, then set the parking brake.
See Parking Brake
on
page 9‑51for more information.
{WARNING
With all-wheel drive, the vehicle
will be free to roll —even if the
shift lever is in P (Park) —if the
transfer case is in Neutral. So, be
sure the transfer case is in a drive
gear, four-wheel high (4H) or
four-wheel low (4L) —not in
Neutral.
2. Move the shift lever into P (Park) by pressing the shift lever button
and moving the lever as far
forward as it will go.
3. Turn the ignition key to LOCK/OFF.
4. Remove the key from the ignition.

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.

Driving and Operating 9-45
You can shift into 1 (First) when
you are going less than 30 km/h
(20 mph). If you have come to a
complete stop and it is hard to shift
into 1 (First), put the shift lever in
Neutral and let up on the clutch.
Then press the clutch pedal back
down and shift into 1 (First).
2 (Second):Press the clutch pedal
as you let up on the accelerator
pedal and shift into 2 (Second).
Then, slowly let up on the clutch
pedal as you press the accelerator
pedal.
3 (Third), 4 (Fourth) and 5 (Fifth):
Shift into 3 (Third), 4 (Fourth) and
5 (Fifth) the same way you do for
2 (Second). Slowly let up on the
clutch pedal as you press the
accelerator pedal.
To stop, let up on the accelerator
pedal and press the brake pedal.
Just before the vehicle stops, press
the clutch pedal and the brake
pedal, and shift to Neutral.
Neutral: Use this position when
you start or idle the engine. R (Reverse):
To back up, stop the
vehicle. Press the clutch pedal and
shift into R (Reverse). Slowly let up
on the clutch pedal as you press
the accelerator pedal. If it is hard
to shift, let the shift lever return to
Neutral and release the clutch
pedal. Then press the clutch again
and shift into R (Reverse). Do not
attempt to shift into the fifth gear
position prior to shifting into
R (Reverse). The transmission has
a lock out feature which prevents a
5 (Fifth) gear to R (Reverse) gear
shift.
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.
Use R (Reverse), along with the
parking brake, for parking the
vehicle.Up-Shift Light
This light will show you when to shift
to the next higher gear for best fuel
economy.
When this light comes on, you
can shift to the next higher gear if
weather, road and traffic conditions
permit. For the best fuel economy,
accelerate slowly and shift when the
light comes on.
While you accelerate, it is normal
for the light to go on and off if you
quickly change the position of the
accelerator. Ignore the shift light
when you downshift.
Disregard the shift light when the
transfer case is in four-wheel low.
For more information, see Up-Shift
Light on page 5‑15.

9-46 Driving and Operating
Shift Speeds
{WARNING
If you skip a gear when you
downshift, you could lose control
of the vehicle. You could injure
yourself or others. Do not shift
down more than one gear at a
time when you downshift.
Hill Start Assist
H3 and H3T vehicles have a Hill
Start Assist feature, which may be
useful when stopped on a grade.
SeeBraking
on page 9‑3for more
information.
Drive Systems
Four-Wheel Drive
Full-Time Four-Wheel Drive sends
engine power to all four wheels for
extra traction. To get the most out of
Full-Time Four-Wheel Drive, you
must be familiar with its operation.
Transfer Case Buttons
The transfer case buttons are
located to the right of the instrument
panel cluster. Use these switches
to shift into and out of the different
Full-Time Four-Wheel Drive modes. 4
m(Four-Wheel High):
This
setting is used for driving in most
street and highway situations. You
can also use this setting for light or
variable off-road conditions.
N (Neutral): Shift the transfer case
to Neutral only when towing the
vehicle. See Driving Characteristics
and Towing Tips
on page 9‑70for
more information.
Notice: Driving on pavement
in Four-Wheel High Lock or
Four Wheel Low Lock for
extended periods may cause
premature wear on the vehicle
powertrain and tires. Do not
drive in Four-Wheel High Lock
or Four-Wheel Low Lock on
pavement for extended periods.
4
m Q(Four-Wheel-High Lock):
Use this setting when you need
extra traction in most off-road
situations such as sand, mud,
snow or level, rocky trails.

Driving and Operating 9-47
Notice:Operating the vehicle
in Four-Wheel-Low Lock above
48 km/h (30 mph) for any
extended period of time could
cause damage to the transfer
case. Do not operate the vehicle
in Four-Wheel-Low Lock above
48 km/h (30 mph) for extended
periods.
4
n Q(Four-Wheel-Low Lock):
This setting delivers extra torque
to all four wheels and is used for
extreme off-road conditions.
If the vehicle has locking axles,
they can be locked for additional
traction in extreme off-road
situations. See Locking Rear Axle
on page 9‑54andLocking Front
Axle on page 9‑55.
Indicator lights in the buttons show
which setting the transfer case is
in. The indicator lights will come
on briefly when the ignition is in
ON/RUN. The If the lights do not
come on, take the vehicle to your
dealer for service. An indicator light will flash while shifting the transfer
case. If the transfer case cannot
make a requested shift, it will return
to the last chosen setting.
If the SERV 4WD message on the
Driver Information Center (DIC)
stays on, take the vehicle to your
dealer for service. See Service 4WD
message under
Driver Information
Center (DIC) on page 5‑18.
Shifting between Four-Wheel High
and Four-Wheel-High Lock
With the vehicle traveling less than
120 km/h (75 mph), press and
release the Four-Wheel High or
Four-Wheel-High Lock button.
It may be necessary to drive
backwards while turning for a
distance of 7.5 m (25 feet) to get
the lock feature to disengage.
Shifting into Four-Wheel Low Lock
Notice: Shifting the transmission
into gear before the indicator
light stops flashing could cause
damage to the transfer case. Always wait until the indicator
light stops flashing before putting
the transmission back in gear.
To shift into Four-Wheel-Low Lock,
the ignition must be in ON/RUN and
the vehicle must be stopped or
moving less than 5 km/h (3 mph)
with the transmission in N (Neutral).
The preferred method for shifting
into Four-Wheel Low is to have
the vehicle moving 1.6 to 3.2 km/h
(1 to 2 mph). Press and release
the Four-Wheel-Low Lock button.
If the vehicle has a manual
transmission, the clutch pedal must
be pressed to the floor while you
press the Four-Wheel-Low Lock
button, or the shift will not be
completed. You must wait for the
Four-Wheel-Low Lock indicator light
to stop flashing and remain lit before
shifting the transmission into gear.
It is normal for the vehicle to have
engagement noise and bump when
shifting between Four-Wheel Low
and Four-Wheel High ranges or
from Neutral.

9-48 Driving and Operating
If the Four-Wheel-Low Lock button
is pressed when the vehicle is in
gear and/or moving too fast, the
Four-Wheel-Low Lock indicator light
will flash for 15 seconds and not
complete the shift.
Shifting Out of
Four-Wheel-Low Lock
Notice:Shifting the transmission
into gear before the indicator
light stops flashing could cause
damage to the transfer case.
Always wait until the indicator
light stops flashing before putting
the transmission back in gear.
To shift out of Four-Wheel-Low
Lock, the vehicle must be stopped
or moving less than 5 km/h (3 mph)
with the transmission in N (Neutral)
and the ignition in ON/RUN. The
preferred method for shifting out of
Four-Wheel-Low Lock is to have
the vehicle moving 1.6 to 3.2 km/h
(1 to 2 mph). Press and release
the Four-Wheel High or
Four-Wheel-High Lock button. If the vehicle has a manual
transmission, the clutch pedal
must be pressed to the floor while
you press the Four-Wheel High
or Four-Wheel-High Lock button,
or the shift will not be completed.
You must wait for the Four-Wheel
High or Four-Wheel-High Lock
indicator light to stop flashing
and remain lit before shifting the
transmission into gear.
It is normal for the vehicle to have
engagement noise and bump when
shifting between Four-Wheel Low
and Four-Wheel High ranges or
from Neutral.
If the Four-Wheel High or
Four-Wheel-High Lock button is
pressed when the vehicle is in
gear and/or moving too fast,
the Four-Wheel High or
Four-Wheel-High Lock indicator
light will flash for 15 seconds
but will not complete the shift.
Shifting Into Neutral
To shift the transfer case to Neutral:
1. Set the parking brake.
2. Start the vehicle.
3. Put the transmission in
N (Neutral). If the vehicle has a
manual transmission, press and
hold the clutch pedal down while
you perform Steps 5 through 9.
4. Shift the transfer case to Four-Wheel High.
{WARNING
Shifting an all-wheel-drive
vehicle's transfer case into
Neutral can cause the vehicle
to roll even if the automatic
transmission is in P (Park) or the
manual transmission is in any
gear. You or others could be
injured. Make sure the parking
brake is firmly set before you shift
the transfer case to Neutral.

Driving and Operating 9-49
5. Simultaneously press andhold the Four-Wheel High and
Four-Wheel-Low Lock buttons
for 10 seconds. The Neutral light
will come on when the transfer
case shift to Neutral is complete.
6. Press and hold the regular brake pedal and shift the transmission
to R (Reverse), then shift the
transmission to D (Drive) for
an automatic transmission,
or 1 (First) for vehicles have a
manual transmission and then
let out the clutch. This is to
ensure the transfer case is in
Neutral. If not, repeat this
procedure starting at Step 3.
7. Turn the engine off. 8. Place the transmission shift
lever in P (Park) for an automatic
transmission, or 1 (First) for
vehicles that have a manual
transmission.
9. Turn the ignition to LOCK/OFF.
Shifting Out of Neutral
To shift out of Neutral:
1. Set the parking brake and apply the regular brake pedal.
2. Shift the transmission to N (Neutral) for an automatic
transmission, or press the clutch
pedal for vehicles that have a
manual transmission. Then turn
the ignition to ON/RUN but do
not start the engine. 3. Press the button for the
desired transfer case shift
position (Four-Wheel High,
Four-Wheel-High Lock or
Four-Wheel-Low Lock).
After the transfer case has
shifted out of Neutral the light
will go out.
4. Release the parking brake.
Notice: Shifting the transmission
into gear before the indicator
light stops flashing could cause
damage to the transfer case.
Always wait until the indicator
light stops flashing before putting
the transmission back in gear.
5. You may start the engine and shift the transmission to the
desired position.

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.