GMC YUKON XL DENALI 2007 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.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 (e.g., under heavy loads and/or hilly
conditions).
You may also want to activate the tow/haul mode
if the transmission shifts too often. See “Tow/Haul
Mode” underTowing a Trailer on page 400.
When towing at high altitude on steep uphill
grades, consider the following: Engine coolant at
or near sea level will boil at a lower temperature
than at higher 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. If you do get the overheat warning,
seeEngine Overheating on page 448.
411

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.
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).
5. Release the regular brakes.
412

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 (don’t overll), 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.
413

Trailer Wiring Harness
Heavy-Duty Trailer Wiring Package
Your vehicle is equipped with the seven-wire
trailer towing harness. This harness with a
seven-pin universal heavy-duty trailer connector is
attached to the rear bumper beam. It is located
next to the integrated trailer hitch.The seven-wire harness contains the following
trailer circuits:
Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
Red w/ Black Stripe: Battery Feed*
Dark Blue: Trailer Brake*
*The fuses for these two circuits are installed in
the underhood electrical center, but the circuits are
not connected. They should be installed by your
dealer or a qualied service center.
If you are charging a remote (non-vehicle) battery,
press the tow/haul mode button located at the
end of the shift lever. This will boost the vehicle
system voltage and properly charge the battery.
If the trailer is too light for tow/haul mode, you can
turn on the headlamps as a second way to
boost the vehicle system and charge the battery.
414

Electric Brake Control Wiring
Provisions
These wiring provisions are included with your
vehicle as part of the heavy-duty trailer wiring
package. These provisions are for an electric
brake controller. The red/black stripe power feed
will not be connected to the battery until the
ring terminal is unstowed and connected to the
underhood electrical center. The instrument panel
contains blunt cut wires near the data link
connector for the trailer brake controller. The
harness contains the following wires:
Dark Blue: Brake Signal to Trailer Connector
Red/Black: Battery
Light Blue/White: Brake Switch
White: Ground
It should be installed by your dealer or a qualied
service center.
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 400.
415

✍NOTES
416

Service........................................................ 420
Accessories and Modications................... 421
California Proposition 65 Warning.............. 421
Doing Your Own Service Work.................. 422
Adding Equipment to the Outside
of Your Vehicle...................................... 423
Fuel............................................................. 423
Gasoline Octane........................................ 423
Gasoline Specications.............................. 424
California Fuel........................................... 424
Additives................................................... 424
Fuels in Foreign Countries........................ 425
Filling the Tank......................................... 426
Filling a Portable Fuel Container............... 428
Checking Things Under the Hood.............. 428
Hood Release........................................... 429
Engine Compartment Overview.................. 430
Engine Oil................................................. 432
Engine Oil Life System.............................. 435Engine Air Cleaner/Filter............................ 437
Automatic Transmission Fluid.................... 440
Engine Coolant.......................................... 445
Coolant Surge Tank Pressure Cap............ 448
Engine Overheating................................... 448
Overheated Engine Protection
Operating Mode..................................... 450
Cooling System......................................... 451
Engine Fan Noise..................................... 456
Power Steering Fluid................................. 457
Windshield Washer Fluid........................... 458
Brakes...................................................... 459
Battery...................................................... 463
Jump Starting............................................ 464
All-Wheel Drive........................................... 469
Rear Axle.................................................... 470
Front Axle................................................... 471
Headlamp Aiming........................................ 473
Section 5 Service and Appearance Care
417

Bulb Replacement....................................... 476
Halogen Bulbs........................................... 476
Taillamps, Turn Signal, Stoplamps and
Back-up Lamps...................................... 476
License Plate Lamp................................... 477
Replacement Bulbs................................... 478
Windshield Wiper Blade Replacement....... 478
Tires............................................................ 480
Tire Sidewall Labeling............................... 482
Tire Terminology and Denitions............... 485
Ination - Tire Pressure............................. 488
High-Speed Operation............................... 490
Tire Pressure Monitor System................... 490
Tire Inspection and Rotation...................... 496
When It Is Time for New Tires.................. 497
Buying New Tires...................................... 498
Different Size Tires and Wheels................ 500
Uniform Tire Quality Grading..................... 501
Wheel Alignment and Tire Balance............ 502
Wheel Replacement.................................. 503
Tire Chains............................................... 504If a Tire Goes Flat.................................... 505
Changing a Flat Tire................................. 506
Removing the Spare Tire and Tools.......... 507
Removing the Flat Tire and Installing
the Spare Tire....................................... 512
Secondary Latch System........................... 518
Storing a Flat or Spare Tire and Tools...... 522
Spare Tire................................................. 526
Appearance Care........................................ 526
Cleaning the Inside of Your Vehicle.......... 526
Fabric/Carpet............................................. 528
Leather...................................................... 529
Instrument Panel, Vinyl, and Other
Plastic Surfaces..................................... 529
Wood Panels............................................. 530
Speaker Covers........................................ 530
Care of Safety Belts.................................. 530
Weatherstrips............................................ 530
Washing Your Vehicle............................... 530
Cleaning Exterior Lamps/Lenses................ 531
Finish Care............................................... 531
Section 5 Service and Appearance Care
418

Windshield, Backglass, and Wiper Blades.... 532
Aluminum Wheels...................................... 532
Tires......................................................... 533
Sheet Metal Damage................................. 533
Finish Damage.......................................... 534
Underbody Maintenance............................ 534
Chemical Paint Spotting............................ 534
Vehicle Care/Appearance Materials............ 535
Vehicle Identication.................................. 535
Vehicle Identication Number (VIN)........... 536
Service Parts Identication Label............... 536Electrical System........................................ 537
Add-On Electrical Equipment..................... 537
Windshield Wiper Fuses............................ 537
Power Windows and Other Power
Options.................................................. 537
Fuses and Circuit Breakers....................... 538
Instrument Panel Fuse Block..................... 538
Center Instrument Panel Fuse Block......... 539
Underhood Fuse Block.............................. 541
Capacities and Specications.................... 546
Section 5 Service and Appearance Care
419

Service
Your dealer knows your vehicle best and wants
you to be happy with it. We hope you will go
to your dealer for all your service needs. You will
get genuine GM parts and GM-trained and
supported service people.We hope you will want to keep your GM vehicle all
GM. Genuine GM parts have one of these marks:
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