2003 GMC YUKON DENALI towing

Towing Loading Your Vehicle
Towing Your Vehicle
Consult your dealer or a professional towing service if
you need to have your disabled vehicle towed. See
Roadside Assistance Program on page
7-5.
If you want to tow your vehicle behind another vehicle
for recreational purposes (such as behind a motorhome),
see “Recreational Vehicle Towing” following.
Recreational Vehicle Towing
Recreational vehicle towing means towing your vehicle
behind another vehicle
- such as behind a motorhome.
The two most common types of recreational vehicle
towing are known as “dinghy towing” (towing your vehicle
with all four wheels on the ground) and “dolly towing”
(towing your vehicle with two wheels
on the ground and
two wheels
up on a device known as a “dolly”).
Your vehicle was not designed
to be towed with any of
its wheels on the ground.
If your vehicle must be
towed, see Towing Your Vehicle on page
4-44.
Notices Towing an all-wheel-drive vehicle with all
four wheels on the ground, or even with only two
of
its wheels on the ground, will damage drivetrain
components. Don’t tow an all-wheel-drive vehicle
if
any of its wheels will be on the ground.
II II
GAWR FRT GAWR RR
!E mNERS MANUAL FOR ADDITIONAL INFORMATION[-]
The Certificationmire label is found on the rear edge of
the driver’s door.
The label shows the size of your original tires and the
inflation pressures needed
to obtain the gross weight
capacity of your vehicle. This is called the GVWR (Gross
Vehicle Weight Rating). The GVWR includes the
weight of the vehicle, all occupants, fuel and cargo.
The Certificationmire label also tells you the maximum
weights for the front and rear axles, called Gross
Axle Weight Rating (GAWR). To find out the actual loads
on your front and rear axles, you need to go
to a
4-44

Automatic Level Control
The automatic level control rear suspension comes as a
part of the AutorideTMsuspension. See AutorideTM on
page
4-46.
This type of level control is fully automatic and will
provide a better leveled riding position as well as better
handling under a variety of passenger and loading
conditions. An air compressor connected
to the rear
shocks will raise or lower the rear of the vehicle
to maintain proper vehicle height. The system is
activated when the ignition key
is turned to RUN and
will automatically adjust vehicle height thereafter.
The system may exhaust (lower vehicle height) for up
to
10 minutes after the ignition key has been turned to
OFF. You may hear the air compressor operating when
the height is being adjusted.
If a weight-distributing hitch is being used, it is
recommended
to allow the shocks to inflate, thereby
leveling the vehicle prior to adjusting the height.
AutorideTM
The AutorideTM feature provides superior vehicle ride
and handling under a variety
of passenger and loading
conditions.
The system is fully automatic and
uses a computer
controller
to continuously monitor vehicle speed, wheel
to body position, IifVdive and steering position of the
vehicle. The controller then sends signals to each shock
absorber
to independently adjust the damping level to
provide the optimum vehicle ride.
AutorideTM also interacts with the towlhaul mode that,
when activated, will provide additional control of
the shock absorbers. This additional control results in
better ride and handling characteristics when the vehicle
is loaded or towing a trailer. See "Tow/Haul Mode"
under Towing a Trailer on page
4-47 for more
information.
4-46

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 figure about
150 Ibs. (68 kg) for each seat. The total cargo load
must
not be more than your vehicle’s CWR.
Weigh your vehicle with the 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, see
Towing a Trailer on
page 4-47.
Towing a Trailer
Is
IOU don’_ Ase e correct equipment anc-
drive properly, you can lose control when you
pull a trailer. For example, if the trailer is too
heavy, the brakes may not work well
-- or even
at all.
You and your passengers could be
seriously injured. Pull a trailer only
if you have
followed all the steps
in this section. Ask your
dealer for advice and information about towing
a trailer with your vehicle.
Nofice: Pulling a trailer improperly can damage
your vehicle and result
in costly repairs not covered
by your warranty.
To pull a trailer correctly, follow
the advice
in this part, and see your dealer for
important information about towing a trailer with
your vehicle. Additional rear axle maintenance
is required for a vehicle used to tow a trailer. See
“Scheduled Maintenance Services” in the Index.
4-47

To identify the trailering capacity for your vehicle, you
should read the information in “Weight of the Trailer” that
appears later in this section.
If yours was built with trailering options, as many are,
it’s ready for heavier trailers. But trailering is different
than just driving your vehicle by itself. Trailering means
changes in handling, durability and fuel economy.
Successful, safe trailering takes correct equipment, and
it has
to be used properly.
That’s the reason for this part. In it are many time-tested,
important trailering tips and safety rules. Many of
these are important for your safety and that of your
passengers.
So please read this section carefully before
you pull a trailer.
0
0
If You Do Decide To Pull A Trailer
If you do, here are some important points:
There are many different laws, including speed limit
restrictions, having
to do with trailering. Make sure
your rig will be legal, not only where you live
but also where you’ll be driving.
A good source for
this information can be state or provincial police. Consider using a
sway control
if your trailer will
weigh
5,000 Ibs. (2 270 kg) or less. You should
always use a sway control
if your trailer will weigh
more than
5,000 Ibs. (2 270 kg). You can ask a
hitch dealer about sway controls.
Don’t tow a trailer at all during the first
500 miles
(800 km) your new vehicle is driven. Your engine,
axle or other parts could be damaged.
Then, during the first
500 miles (800 km) that you
tow a trailer, don’t drive over
50 mph (80 km/h)
and don’t make starts at full throttle. This helps your
engine and other parts of your vehicle wear in at
the heavier loads.
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). See “Tow/Haul Mode” under Towing
a
Trailer on page 4-47.
Three important considerations have to do with weight:
0 the weight of the trailer,
the weight of the trailer tongue
0 and the weight on your vehicle’s tires.
4-48

Driving with a Trailer
If you have a rear-most window open and you
pull a trailer with your vehicle, carbon
monoxide (CO) could come into your vehicle.
You can’t see or smell CO.
It can cause
unconsciousness or death. See “Engine
Exhaust” in the Index.
To maximize your safety
when towing a trailer:
Have your exhaust system inspected for
leaks, and make necessary repairs before
starting on your trip.
Keep the rear-most windows closed.
If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main
heating or cooling system on and with the
fan on any speed. This will bring fresh,
outside air into your vehicle.
Do not use
the comfort control setting for maximum
air because
it only recirculates the air
inside your vehicle. See “Comfort
1 Controls” in the Index. Towing a trailer requires a certain amount
of experience.
Before setting out for the open road, you’ll want to get
to know your rig. Acquaint yourself with the feel of
handling and braking with the added weight of the trailer.
And always keep
in mind that the vehicle you are
driving is now a good deal longer and not nearly as
responsive as your vehicle is by itself.
Before you start, check the trailer hitch and platform
(and attachments), safety chains, electrical connector,
lamps, tires and mirror adjustment.
If the trailer has
electric brakes, start your vehicle and trailer moving and
then apply the trailer brake controller by hand to be
sure the brakes are working. This lets you check your
electrical connection at the same time.
During your trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer
brakes are still working.
Following Distance
Stay at least twice as far behind the vehicle ahead a5
you would when driving your vehicle without a trailer.
This can help you avoid situations that require
heavy braking and sudden turns.
Passing
You’ll need more passing distance up ahead when
you’re towing a trailer. And, because you’re a good deal
longer, you’ll need to go much farther beyond the
passed vehicle before you can return to your lane.
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Backing Up
Hold the bottom of the steering wheel with one hand.
Then,
to move the trailer to the left, just 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. Your vehicle could
be damaged. Avoid
making very sharp turns while trailering.
When you’re turning with a trailer, make wider turns
than normal.
Do this so your 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 your instrument panel will flash whenever
you signal a turn or lane change. Properly hooked up,
the trailer lamps will also flash, telling other drivers
you’re about
to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument panel will flash for turns even
if the bulbs on the trailer
are burned out. Thus, you may think drivers behind
4-54
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 gear before 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”
under Towing a Trailer
on page 4-47.
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. If you do get
the overheat warning, see Engine Overheating
on
page 5-25.

Parking on Hills
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
2. Have someone place chocks under the trailer
3. When the wheel chocks are in place, release the
PARK
(P) yet.
wheels.
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
5. Release the regular brakes.
parking brake
and shift into PARK
(P).
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 fluid (don’t overfill),
engine
oil, axle lubricant, belts, cooling system and
brake system. Each
of these is covered in this manual,
and the Index will help you find 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.
4-55

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 a bracket
on the hitch platform. The Center High-Mounted Stoplamp
(CHMSL) wire is
tied next
to the trailer wiring harness for use with a
trailer.
The seven-wire harness contains the following trailer
circuits:
0 Yellow: Left Stop/Turn Signal
Dark Green: Right Stop/Turn Signal
Brown: Taillamps
White: Ground
Light Green: Back-up Lamps
0 Red: Battery Feed
Dark Blue: Trailer Brake
4-56