wheel HUMMER H3 2010 Workshop Manual

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.

Driving and Operating 9-53
Examples of these conditions
include hard acceleration in a turn,
an abrupt upshift or downshift of the
transmission or driving on rough
roads.
If cruise control is being used when
TCS begins to limit wheel spin,
the cruise control automatically
disengages. The cruise control
can be re-engaged when road
conditions allow. SeeCruise Control
on page 9‑57for more information.
TRACTION FAILED appears on the
Driver information Center (DIC)
when a TCS or antilock brake
system problem has been detected
and the vehicle needs service.
When this message is on, the
system will not limit wheel spin.
Adjust your driving accordingly.
See Driver Information Center (DIC)
on page 5‑18for more information.
It is recommended to leave the
system on for normal driving
conditions, but it may be necessary
to turn the system off if the vehicle
is stuck in sand, mud, ice, or snow, and it is necessary to
“rock”the
vehicle to attempt to free it. See If
the Vehicle is Stuck
on page 9‑26for more information.
To turn the system off, press and
release the TCS/StabiliTrak button.
When TCS has been turned off, this
light comes on steady and TRAC
OFF appears on the DIC. This light
flashes when TCS is active.
Press and release the
TCS/StabiliTrak button again to
turn the system back on. The TRAC
OFF message then goes off. TCS automatically comes on
whenever the vehicle is started and
resets itself at each ignition cycle.
Adding non‐dealer/non‐retailer
accessories can affect the vehicle's
performance. See
Accessories and
Modifications on page 10‑3.
StabiliTrak System
The vehicle has a vehicle stability
enhancement system called
StabiliTrak. It is an advanced
computer controlled system that
assists the driver with directional
control of the vehicle in difficult
driving conditions.
StabiliTrak activates when the
computer senses a difference
between the intended path and the
direction the vehicle is actually
traveling. StabiliTrak selectively
applies braking pressure at any
one of the vehicle's brakes to assist
the driver with keeping the vehicle
on the intended path.

9-54 Driving and Operating
When the vehicle is started and
begins to move, the system
performs several diagnostic checks
to insure there are no problems.
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.
If cruise control is being used when
StabiliTrak activates, the cruise
control automatically disengages.
The cruise control can be
re-engaged when road conditions
allow. SeeCruise Control
on
page 9‑57.
If there is a problem detected with
StabiliTrak, a SERVICE STAB SYS
message displays on the Driver
Information Center (DIC). See
Driver Information Center (DIC)
on
page 5‑18for more information.
When this message is displayed,
the system is not working. Adjust
your driving accordingly. StabiliTrak comes on automatically
whenever the vehicle is started and
resets itself at each ignition cycle.
However, when the transfer case is
placed in Four‐Wheel‐Low Lock
mode, StabiliTrak is automatically
disabled. See
Four-Wheel Drive
on
page 9‑46for more information.
It is recommended to leave the
system on for normal driving
conditions, but it may be necessary
to turn the system off if the vehicle
is stuck in sand, mud, ice, or snow,
and it is necessary to “rock”the
vehicle to attempt to free it. See If
the Vehicle is Stuck
on page 9‑26.
This light comes on steady when
TCS has been turned off. This light
flashes when StabiliTrak is active. To Turn off TCS and StabiliTrak,
press and hold the TCS/StabiliTrak
button until STAB SYS OFF
displays on the DIC. Press and
release the TCS/StabiliTrak button
again to turn StabiliTrak back on.
Locking Rear Axle
For vehicles with this feature,
additional traction can be obtained
from the rear wheels when traveling
in off-road situations such as mud,
snow, sand, steep hills and uneven
terrain.
The button used to turn this
feature on or off is located on the
instrument panel.

Driving and Operating 9-55
To lock the rear axle, do the
following:
1. Place the transfer case in the4LO Lock mode. This is the
only mode which will allow
the rear axle to lock. See
Four-Wheel Drive
on page 9‑46for more information regarding
the transfer case and
4LO Lock mode.
2. Press the rear axle locking button with the vehicle moving
less than 26 km/h (16 mph).
The light in the button stops flashing
and remains illuminated when the
rear axle is locked.
Notice: If you try to lock the axle
while the vehicle is stuck and the
tires are spinning, the vehicle's
drivetrain could be damaged. The repairs would not be covered
by the vehicle warranty. Always
lock the axle before attempting
situations and/or navigating
terrain which could possibly
cause the vehicle to become
stuck.
The locking rear axle will be
disengaged when the wheel speed
is greater than 64 km/h (40 mph),
if the vehicle's battery is low and/or
the transfer case is shifted out of
4LO Lock mode.
Notice:
If the vehicle's axle
is locked while driving on
pavement, the drivetrain could be
damaged. Repairs would not be
covered by the vehicle warranty.
Do not use the locking axle on
pavement. If four-wheel drive is
needed when traveling on
pavement, use only 4HI.
Locking Front Axle
For vehicles with this feature, the
locking front axle, used with the
locking rear axle, can give the
vehicle additional traction when
traveling in off-road situations such
as mud, snow, sand, steep hills and
uneven terrain.
The button used to turn the locking
front axle on or off is located on the
instrument panel.
Before the front axle can be locked,
the rear axle must be locked.

9-56 Driving and Operating
To lock the front and rear axles:
1. Place the transfer case in the4LO Lock mode. This is the
only mode which allows the
front and rear axles to lock.
See Four-Wheel Drive
on
page 9‑46for more information
regarding the transfer case and
4LO Lock mode.
2. Press the rear axle locking button with the vehicle moving
less than 16 mph (26 km/h).
3. Wait for the light in the button to stop flashing and remain
illuminated to show that the rear
axle is locked.
4. Press the front axle locking button with the vehicle stopped
or moving less than 26 km/h
(16 mph). 5. Wait for the light in the button
to stop flashing and remain
illuminated to show that the front
axle is locked.
Notice: If you try to lock the axle
while the vehicle is stuck and the
tires are spinning, the vehicle's
drivetrain could be damaged.
The repairs would not be covered
by the vehicle warranty. Always
lock the axle before attempting
situations and/or navigating
terrain which could possibly
cause the vehicle to become
stuck. Locking axles will be disengaged
when the wheel speed is greater
than 64 km/h (40 mph), if the
vehicle's battery is low and/or the
transfer case is shifted out of
4LO Lock mode.
Notice:
If the vehicle's axle
is locked while driving on
pavement, the drivetrain could be
damaged. Repairs would not be
covered by the vehicle warranty.
Do not use the locking axle on
pavement. If four-wheel drive is
needed when traveling on
pavement, use only 4HI.

Driving and Operating 9-57
Cruise Control
With cruise control, a speed of
about 40 km/h (25 mph) or more can
be maintained without keeping your
foot on the accelerator. Cruise
control does not work at speeds
below about 40 km/h (25 mph).
9(Off): Turns the cruise control
system off.
R (On): Turns the cruise control the
system on.
S(Resume/Accelerate): Makes
the vehicle accelerate or resume to
a previously set speed.
rT (Set): Press this button to set
the speed.
Cruise control will not work if the
parking brake is set, or if the master
cylinder brake fluid level is low.
If the brakes are applied, the cruise
control shuts off.
{WARNING
Cruise control can be dangerous
where you cannot drive safely at
a steady speed. So, do not use
the cruise control on winding
roads or in heavy traffic.
(Continued)
WARNING (Continued)
Cruise control can be dangerous
on slippery roads. On such roads,
fast changes in tire traction can
cause excessive wheel slip, and
you could lose control. Do not use
cruise control on slippery roads.
The cruise control disengages, if the
vehicle has the Traction Control
System (TCS) and it begins to limit
wheel spin. See Traction Control
System (TCS)
on page 9‑52.
When road conditions allow the
cruise control to be safely used
again, it can be turned back on.

Driving and Operating 9-71
With the added weight, the engine,
transmission, wheel assemblies and
tires are forced to work harder and
under greater loads. The trailer also
adds wind resistance, increasing
the pulling requirements. For safe
trailering, correctly use the proper
trailering equipment.
The following information has
important trailering tips and rules
for your safety and that of your
passengers. Read this section
carefully before pulling a trailer.
Pulling A Trailer
Here are some important points:
.There are many laws, including
speed limit restrictions that apply
to trailering. Check for legal
requirements with state or
provincial police.
.Consider using a sway control.
See“Hitches” later in this
section.
.Do not tow a trailer at all during
the first 800 km (500 miles) the
new vehicle is driven. The
engine, axle or other parts could
be damaged.
.Then, during the first 800 km
(500 miles) that a trailer is
towed, do not drive over 80 km/h
(50 mph) and do not make starts
at full throttle. This helps the
engine and other parts of the
vehicle wear in at the heavier
loads.
.Vehicles with an automatic
transmission can tow in
D (Drive). Use a lower gear if
the transmission shifts too often.
For vehicles with a manual
transmission, it is better not to
use the highest gear.
.This vehicle has a Hill Start
Assist feature, which may be
useful when the vehicle is
stopped on a grade. See Hill
Start Assist (HSA)
on page 9‑52for more information.
.Do not drive faster than the
maximum posted speed for
trailers.
Driving with a Trailer
Towing a trailer requires experience.
Get familiar with handling and
braking with the added trailer
weight. The vehicle is now longer
and not as responsive as the
vehicle is by itself.
Check all trailer hitch parts and
attachments, safety chains,
electrical connectors, lamps, tires
and mirror adjustments. If the trailer
has electric brakes, start the vehicle
and trailer moving and then apply
the trailer brake controller by hand
to be sure the brakes are working.
During the trip, check occasionally
to be sure that the load is secure,
and the lamps and trailer brakes are
working properly.

9-72 Driving and Operating
Towing with a Stability Control
System
When towing, the sound of the
stability control system might be
heard. The system is reacting to the
vehicle movement caused by the
trailer, which mainly occurs during
cornering. This is normal when
towing heavier trailers.
Following Distance
Stay at least twice as far behind the
vehicle ahead as you would when
driving the vehicle without a trailer.
This can help to avoid situations
that require heavy braking and
sudden turns.
Passing
More passing distance is needed
when towing a trailer. Because the
rig is longer, it is necessary to go
much farther beyond the passed
vehicle before returning to the lane.
Backing Up
Hold the bottom of the steering
wheel with one hand. Then, to move
the trailer to the left, move that hand
to the left. To move the trailer to the
right, move your hand to the right.
Always back up slowly and,
if possible, have someone
guide you.
Making Turns
Notice:Making very sharp turns
while trailering could cause the
trailer to come in contact with the
vehicle. The vehicle could be
damaged. Avoid making very
sharp turns while trailering.
When turning with a trailer, make
wider turns than normal. Do this
so the trailer won't strike soft
shoulders, curbs, road signs, trees
or other objects. Avoid jerky or
sudden maneuvers. Signal well in
advance.
Turn Signals When Towing a
Trailer
The arrows on the instrument panel
flash whenever signaling a turn or
lane change. Properly hooked up,
the trailer lamps also flash, telling
other drivers the vehicle is turning,
changing lanes or stopping.
When towing a trailer, the arrows on
the instrument panel flash for turns
even if the bulbs on the trailer are
burned out. For this reason you
may think other drivers are seeing
the signal when they are not. It is
important to check occasionally to
be sure the trailer bulbs are still
working.
Driving On Grades
Reduce speed and shift to a
lower gear before starting down a
long or steep downgrade. If the
transmission is not shifted down, the
brakes might have to be used so
much that they would get hot and no
longer work well.

Driving and Operating 9-73
Vehicles with an automatic
transmission can tow in D (Drive).
Shift the transmission to a lower
gear if the transmission shifts too
often under heavy loads and/or
hilly conditions. For vehicles with a
manual transmission, it is better not
to use the highest gear.
When towing at high altitude on
steep uphill grades, consider the
following: Engine coolant will boil at
a lower temperature than at normal
altitudes. If the engine is turned off
immediately after towing at high
altitude on steep uphill grades, the
vehicle may show signs similar to
engine overheating. To avoid this,
let the engine run while parked,
preferably on level ground, with the
automatic transmission in P (Park)
for a few minutes before turning the
engine off. For vehicles with manualtransmissions, let the engine run
while parked, preferably on level
ground, with the transmission out of
gear and the parking brake applied,
for a few minutes before turning the
engine off. If the overheat warning
comes on, see
Engine Overheating
on page 10‑22.
Parking on Hills
{WARNING
Parking the vehicle on a hill
with the trailer attached can be
dangerous. If something goes
wrong, the rig could start to move.
People can be injured, and both
the vehicle and the trailer can be
damaged. When possible, always
park the rig on a flat surface. If parking the rig on a hill:
1. Press the brake pedal, but do
not shift into P (Park) yet for
vehicles with an automatic
transmission, or into gear
for vehicles with a manual
transmission. Turn the wheels
into the curb if facing downhill
or into traffic if facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the brake pedal
until the chocks absorb the load.
4. Reapply the brake pedal. Then apply the parking brake and shift
into P (Park) for vehicles with an
automatic transmission or into
gear for vehicles with a manual
transmission.
5. Release the brake pedal.

Vehicle Care 10-1
Vehicle Care
General Information
General Information . . . . . . . . . . 10-2
California Proposition65 Warning . . . . . . . . . . . . . . . . . 10-2
California Perchlorate Materials Requirements . . . . 10-3
Accessories and Modifications . . . . . . . . . . . . . . . 10-3
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 10-4
Hood . . . . . . . . . . . . . . . . . . . . . . . . 10-5
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . 10-6
Engine Oil . . . . . . . . . . . . . . . . . . . 10-9
Engine Oil Life System . . . . . 10-11
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . 10-12
Manual Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . 10-15 Hydraulic Clutch . . . . . . . . . . . . 10-16
Engine Air Cleaner/Filter . . . . 10-17
Cooling System . . . . . . . . . . . . 10-18
Engine Coolant . . . . . . . . . . . . . 10-19
Engine Overheating . . . . . . . . 10-22
Engine Fan . . . . . . . . . . . . . . . . . 10-24
Power Steering Fluid . . . . . . . 10-24
Washer Fluid . . . . . . . . . . . . . . . 10-25
Brakes . . . . . . . . . . . . . . . . . . . . . 10-26
Brake Fluid . . . . . . . . . . . . . . . . . 10-27
Battery . . . . . . . . . . . . . . . . . . . . . 10-28
Four-Wheel Drive . . . . . . . . . . . 10-29
Front Axle . . . . . . . . . . . . . . . . . . 10-29
Rear Axle . . . . . . . . . . . . . . . . . . 10-29
Starter Switch Check . . . . . . . 10-30
Automatic Transmission Shift
Lock Control System
Check . . . . . . . . . . . . . . . . . . . . . 10-30
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . 10-31
Park Brake and P (Park) Mechanism Check . . . . . . . . 10-31
Wiper Blade Replacement . . . . . . . . . . . . . . 10-32
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . 10-33
Bulb Replacement
Bulb Replacement . . . . . . . . . . 10-35
Halogen Bulbs . . . . . . . . . . . . . . 10-35
Headlamps . . . . . . . . . . . . . . . . . 10-35
Taillamps, Turn Signal,Stoplamps, and Back-Up
Lamps (H3) . . . . . . . . . . . . . . . 10-35
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps (H3T) . . . . . . . . . . . . . . 10-36
License Plate Lamp . . . . . . . . 10-37
Replacement Bulbs . . . . . . . . . 10-37
Electrical System
Electrical System Overload . . . . . . . . . . . . . . . . . . 10-38
Fuses and Circuit Breakers . . . . . . . . . . . . . . . . . . 10-39
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . 10-39