towing HUMMER H3 2006 Owner's Manual

Driving On Grades
Reduce speed and shift to a lower gearbeforeyou start
down a long or steep downgrade. If you don’t shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
If you have an automatic transmission, you can tow in
DRIVE (D). You may want to shift the transmission
to THIRD (3) or, if necessary, a lower gear selection if
the transmission shifts too often under heavy loads
and/or hilly conditions.
If you have a manual transmission and you are towing a
trailer, 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 you turn your
engine off immediately after towing at high altitude
on steep uphill grades, your 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 PARK (P) for a few
minutes before turning the engine off. For manual
transmissions, 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 you do get the overheat
warning, seeEngine Overheating on page 5-27.
Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet for an automatic transmission, or into
gear for a manual transmission. Turn your 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
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your parking
brake and shift into PARK (P) for an automatic
transmission or into gear for a manual transmission.
5. Release the regular brakes.
4-67

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 or a qualied service center. Also, see
Add-On Electrical Equipment on page 5-95for more
information.
4-68

Heavy-Duty Trailer Wiring Package
If your vehicle is equipped with a trailer towing package,
the rear bumper harness will have a seven-pin
universal heavy-duty trailer connector attached to a
bracket on the hitch platform.
The trailer towing harness contains the following
seven trailer circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Red: Battery Feed
Dark Blue: Trailer Brake
Four-Wire Harness Adapter
If you need to tow a light-duty trailer with a standard
four-way, at pin connector, an adapter is available from
your dealer.
Use this adapter to
connect a standard
four-way pin connector to
the seven-wire harness
on your vehicle.
4-69

Connect the adapter with the tab pointing up. The ip
cap on the vehicle’s seven-wire harness will lock
onto the tab (see arrow in the previous graphic) and
help hold the adapter in place. Plug the four-way
pin connector onto the adapter.
Trailer Recommendations
You must subtract your hitch loads from the Cargo
Weight Rating (CWR). CWR is the maximum weight of
the load your vehicle can carry. It doesn’t include
the weight of the people inside, but you can gure about
150 lbs. (68 kg) for each seat. The total cargo load
must not be more than your vehicles CWR.
Weigh your vehicle with your trailer attached, so that
you won’t go over the GVWR or GAWR. If you are using
a weight-distributing hitch, weigh the vehicle without
the spring bars in place.
You’ll get the best performance if you spread out the
weight of your load the right way, and if you choose the
correct hitch and trailer brakes.
For more information seeTowing a Trailer on page 4-59.
4-70

If No Steam Is Coming From Your
Engine
If you get an engine overheat warning but see or hear
no steam, the problem may not be too serious.
Sometimes the engine can get a little too hot when you:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer. See “Driving on Grades” under
Towing a Trailer on page 4-59.
If you get the overheat warning with no sign of steam,
try this for a minute or so:
1. In heavy traffic, let the engine idle in NEUTRAL
while stopped. If it is safe to do so, pull off the
road, shift to PARK (P) or NEUTRAL and let the
engine idle.
2. Turn off the air conditioning.
3. Turn on your heater to full hot at the highest fan
speed and open the windows as necessary.If you no longer have the overheat warning, you can
drive. Just to be safe, drive slower for about 10 minutes.
If the warning does not come back on, you can drive
normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there is still no sign of steam, idle the engine for
three minutes while you are parked. Push down
the accelerator until the engine speed is about twice as
fast as normal idle speed for at least three minutes
while you are parked. If you still have the warning,
turn off the engine and get everyone out of the vehicle
until it cools down.
You may decide not to lift the hood but to get service
help right away.
5-28

6. Start the engine and let it run until you can feel the
upper radiator hose getting hot. Watch out for the
engine cooling fan.
7. By this time, the coolant level inside the radiator
ller neck may be lower. If the level is lower, add
more of the proper DEX-COOL
®coolant mixture
through the ller neck until the level reaches
the base of the ller neck.
Then replace the pressure cap. At any time during
this procedure if coolant begins to ow out of the
ller neck, reinstall the pressure cap. Be sure
to secure it tightly.
Engine Fan Noise
This vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the clutch is not engaged. This improves fuel
economy and reduces fan noise. Under heavy vehicle
loading, trailer towing and/or high outside temperatures,
the fan speed increases when the clutch engages.
So you may hear an increase in fan noise. This is
normal and should not be mistaken as the transmission
slipping or making extra shifts. It is merely the cooling
system functioning properly. The fan will slow down
when additional cooling is not required and the clutch
disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch disengages.
5-33

(h)Change automatic transmission uid and lter if the
vehicle is mainly driven under one or more of these
conditions:
In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as found in taxi, police, or delivery
service.
(i)Drain, ush, and rell cooling system. This service
can be complex; you should have your dealer perform
this service. See Engine Coolant on page 5-24 for
what to use. Inspect hoses. Clean radiator, condenser,
pressure cap, and ller neck. Pressure test the
cooling system and pressure cap.
(j)A uid loss in any vehicle system could indicate a
problem. Have the system inspected and repaired and
the uid level checked. Add uid if needed.
(k)Visually inspect belt for fraying, excessive cracks, or
obvious damage. Replace belt if necessary.Owner Checks and Services
These owner checks and services should be performed
at the intervals specied to help ensure the safety,
dependability and emission control performance of your
vehicle. Your GM Goodwrench
®dealer can assist
you with these checks and services.
Be sure any necessary repairs are completed at once.
Whenever any uids or lubricants are added to your
vehicle, make sure they are the proper ones, as shown
inRecommended Fluids and Lubricants on page 6-12.
At Each Fuel Fill
It is important to perform these underhood checks at
each fuel ll.
Engine Oil Level Check
Check the engine oil level and add the proper oil
if necessary. SeeEngine Oil on page 5-13for
further details.
Notice:It is important to check your oil regularly
and keep it at the proper level. Failure to keep your
engine oil at the proper level can cause damage
to your engine not covered by your warranty.
6-8

Radios (cont.)
Navigation/Radio System, see Navigation
Manual...................................................3-76
Radio with CD............................................3-49
Radio with Six-Disc CD................................3-63
Setting the Time..........................................3-49
Theft-Deterrent............................................3-76
Understanding Reception..............................3-76
Reading Lamps..............................................3-19
Rear Axle......................................................5-45
Locking......................................................4-10
Rear Safety Belt Comfort Guides......................1-25
Rear Seat Passengers, Safety Belts..................1-22
Rear Storage Area..........................................2-45
Rear Windshield Washer/Wiper.........................3-10
Rearview Mirror, Automatic Dimming with
Compass and Temperature Display................2-33
Reclining Seatbacks.......................................... 1-4
Recommended Fluids and Lubricants.................6-12
Recovery Loops..............................................4-51
Recreational Vehicle Towing.............................4-57
Remote Keyless Entry System............................ 2-4
Remote Keyless Entry System, Operation............ 2-5
Removing the Flat Tire and Installing the
Spare Tire..................................................5-77Removing the Spare Tire and Tools...................5-75
Replacement Bulbs.........................................5-51
Reporting Safety Defects
Canadian Government..................................7-11
General Motors...........................................7-11
United States Government............................7-10
Restraint System Check
Checking the Restraint Systems....................1-65
Replacing Restraint System Parts
After a Crash..........................................1-66
Retained Accessory Power (RAP)......................2-16
Right Front Passenger Position, Safety Belts......1-22
Roadside
Assistance Program....................................... 7-6
Rocking Your Vehicle to Get it Out....................4-50
Running the Engine While Parked.....................2-32
S
Safety Belt
Passenger Reminder Light............................3-27
Pretensioners..............................................1-27
Reminder Light............................................3-27
10

Towing
Recreational Vehicle.....................................4-57
Towing a Trailer..........................................4-59
Your Vehicle...............................................4-57
Traction
Control System (TCS).................................... 4-9
Off Light.....................................................3-33
StabiliTrak
®System.....................................4-11
Trailer
Recommendations.......................................4-70
Transmission
Fluid, Automatic...........................................5-19
Fluid, Manual..............................................5-22
Up-Shift Light..............................................3-31
Transmission Operation, Automatic....................2-18
Transmission Operation, Manual........................2-21
Trip Odometer................................................3-26
Turn and Lane-Change Signals.......................... 3-8
Turn Signal/Multifunction Lever........................... 3-7
U
Understanding Radio Reception........................3-76
Uniform Tire Quality Grading............................5-68
Universal Home Remote System.......................2-38
Operation...................................................2-39
Up-Shift Light.................................................3-31
V
Vehicle
Control........................................................ 4-5
Damage Warnings........................................... iv
Loading......................................................4-52
Parking Your...............................................2-30
Symbols......................................................... iv
Vehicle Data Collection and Event Data
Recorders.................................................... 7-9
Vehicle Identication
Number (VIN).............................................5-94
Service Parts Identication Label...................5-95
Ventilation Adjustment......................................3-23
Visors...........................................................2-11
W
Warning Lights, Gages and Indicators................3-24
Warnings
DIC Warnings and Messages........................3-44
Hazard Warning Flashers............................... 3-6
Other Warning Devices.................................. 3-6
Safety and Symbols......................................... iii
Vehicle Damage.............................................. iv
13