2007 HUMMER H3 Owners Manual

Turn Signals When Towing a Trailer
The arrows on your instrument panel will ash
whenever you signal a turn or lane change.
Properly hooked up, the trailer lamps will also ash,
telling other drivers you’re about to turn, change
lanes or stop.
When towing a trailer, the arrows on your
instrument panel will ash for turns even if the bulbs
on the trailer are burned out. Thus, you may think
drivers behind you are seeing your signal when
they are not. It’s important to check occasionally to
be sure the trailer bulbs are still working.
Driving On Grades
Reduce speed and shift to a lower gearbefore
you 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 338.
305

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.
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.
306

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, seeAdd-On Electrical Equipment
on page 416for more information.
307

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
If you are charging a remote (non-vehicle) battery,
turn on the headlamps to boost the vehicle
system voltage to properly charge the battery.
308

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.
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.
309

Trailer Brake Control Wiring Harness
The trailer brake control wiring harness is located
under the instrument panel to the right of the
steering column. The wires are taped to the
harness that goes to the courtesy light under
the instrument panel. The harness will contain
the following wires:
Red Wire: AUX B+
Black Wire: Ground
Light Blue Wire: Brake Signal
Dark Blue Wire: Trailer Brakes
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 297.
310

Service........................................................ 314
Accessories and Modications................... 314
California Proposition 65 Warning.............. 315
Doing Your Own Service Work.................. 315
Adding Equipment to the Outside
of Your Vehicle...................................... 316
Fuel............................................................. 316
Gasoline Octane........................................ 316
Gasoline Specications.............................. 316
California Fuel........................................... 316
Additives................................................... 317
Fuels in Foreign Countries........................ 318
Filling the Tank......................................... 318
Filling a Portable Fuel Container............... 320
Checking Things Under the Hood.............. 321
Hood Release........................................... 321
Engine Compartment Overview.................. 322
Engine Oil................................................. 323Engine Oil Life System.............................. 326
Engine Air Cleaner/Filter............................ 328
Automatic Transmission Fluid.................... 329
Manual Transmission Fluid........................ 332
Hydraulic Clutch........................................ 334
Engine Coolant.......................................... 335
Radiator Pressure Cap.............................. 338
Engine Overheating................................... 338
Cooling System......................................... 340
Engine Fan Noise..................................... 345
Power Steering Fluid ................................. 345
Windshield Washer Fluid........................... 346
Brakes...................................................... 347
Battery...................................................... 351
Jump Starting............................................ 352
Rear Axle.................................................... 357
Four-Wheel Drive........................................ 358
Front Axle................................................... 358
Section 5 Service and Appearance Care
311

Headlamp Aiming........................................ 358
Bulb Replacement....................................... 361
Halogen Bulbs........................................... 361
Headlamps................................................ 362
Taillamps, Turn Signal, Stoplamps
and Back-up Lamps............................... 363
License Plate Lamp................................... 364
Replacement Bulbs................................... 365
Windshield Wiper Blade Replacement....... 366
Tires............................................................ 367
Tire Sidewall Labeling............................... 368
Tire Terminology and Denitions............... 372
Ination - Tire Pressure............................. 375
Tire Pressure Monitor System................... 376Tire Inspection and Rotation...................... 381
When It Is Time for New Tires.................. 383
Buying New Tires...................................... 383
Different Size Tires and Wheels................ 385
Uniform Tire Quality Grading..................... 386
Wheel Alignment and Tire Balance............ 387
Wheel Replacement.................................. 387
Tire Chains............................................... 389
If a Tire Goes Flat.................................... 390
Changing a Flat Tire................................. 391
Removing the Spare Tire and Tools.......... 393
Removing the Flat Tire and Installing
the Spare Tire....................................... 396
Storing a Flat or Spare Tire and Tools...... 403
Spare Tire................................................. 405
Section 5 Service and Appearance Care
312