2003 GMC YUKON DENALI brakes

The heavier the rain, the harder it is to see. Even if your
windshield wiper blades are in good shape, a heavy
rain can make it harder to see road signs and
traffic signals, pavement markings, the edge of the road
and even people walking.
It’s wise to keep your wiping equipment in good shape
and keep your windshield washer tank filled with
washer fluid. Replace your windshield wiper inserts
when they show signs of streaking or missing areas on
the windshield, or when strips of rubber start to
separate from the inserts. Driving too fast through large
water puddles or even
going through some car washes can cause problems,
too. The water may affect your brakes. Try to avoid
puddles. But
if you can’t, try to slow down before
you hit them.
Wet brakes can cause accidents. They won’t
work as well in a quick stop and may cause
pulling to one side. You could lose control
of
the vehicle.
After driving through a large puddle
of water
or a car wash, apply your brake pedal lightly
until your brakes work normally.
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0 Keep your vehicle in good shape. Check all fluid
levels and also the brakes, tires, cooling system
and transmission. These parts can work hard
on mountain roads.
Know how to go down hills. The most important
thing to know is this: let your engine do some of
the slowing down. Shift
to a lower gear when you go
down a steep or long hill.
_. you c tt : ft down, your brakes could get
so hot that they wouldn’t work well. You would
then have poor braking or even none going down
a hill. You could crash. Shift down to let
your engine assist your brakes on
a steep
downhill slope.
L,ast,,,, ,ownh,,, NEUTrlmL (N) or with the
ignition
off is dangerous. Your brakes will have
to do all the work
of slowing down. They could
get so hot that they wouldn’t work well. You
would then have poor braking
or even none
going down
a hill. You could crash. Always
have your engine running and your vehicle in
gear when you go downhill.
Know how to go uphill. You may want to shift down
to a lower gear. The lower gears help cool your
engine and transmission, and you can climb the
hill better.
Stay in your own lane when driving on two-lane
roads in hills or mountains. Don’t swing wide or
cut across the center of the road. Drive at speeds
that let you stay in your own lane.
As you go over the top of a hill, be alert. There
could be something in your lane, like a stalled car or
an accident.
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Driving on Snow or Ice
Most of the time, those places where your tires meet
the road probably have good traction.
However,
if there is snow or ice between your tires and
the road, you can have a very slippery situation.
You’ll have a
lot less traction or “grip” and will need to
be very careful.
27
3
What’s the worst time for this? “Wet ice.” Very cold
snow or ice can be slick and hard
to drive on. But wet
ice can be even more trouble because it may offer
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the least traction of all. You can get wet ice when it’s
about freezing
(32°F; OOC) and freezing rain begins
to fall. Try to avoid driving on wet ice until salt and sand
crews can get there.
Whatever the condition
- smooth ice, packed, blowing
or loose snow
- drive with caution.
Accelerate gently. Try not to break the fragile traction.
If you accelerate
too fast, the drive wheels will spin and
polish the surface under the tires even more.
Your anti-lock brakes improve your vehicle’s stability
when you make a hard stop on a slippery road.
Even though you have an anti-lock braking system,
you’ll want to begin stopping sooner than you would on
dry pavement. See Braking on page
4-6.
Allow greater following distance on any
slippery road.
Watch for slippery spots. The road might be fine
until you hit a spot that’s covered with ice. On
an otherwise clear road, ice patches may appear in
shaded areas where the sun can’t reach: around
clumps of trees, behind buildings or under bridges.
Sometimes the surface of a curve or an overpass
may remain icy when the surrounding roads
are clear. If you see a patch of ice ahead of you,
brake before you are on it. Try not
to brake
while you’re actually on the ice, and avoid sudden
steering maneuvers.

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

Hitches Safety Chains
It’s important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough roads are
a few reasons why you’ll need the right hitch. Here
are some rules
to follow:
If you’ll be pulling a trailer that, when loaded, will
weigh more than
5,000 Ibs. (2 270 kg), be sure to
use a properly mounted, weight-distributing
hitch and sway control of the proper size. This
equipment is very important for proper vehicle
loading and good handling when you’re driving.
Will you have to make any holes in the body of
your vehicle when you install a trailer hitch?
If you do, then be sure to seal the holes later when
you remove the hitch. If you don’t seal them,
deadly carbon monoxide (CO) from your exhaust
can get into your vehicle. See Engine Exhaust
on
page 2-29. Dirt and water can, too.
You should always attach chains between your vehicle
and your trailer. Cross the safety chains under the
tongue of the trailer
to help prevent the tongue from
contacting the road
if it becomes separated from
the hitch. Always leave just enough slack
so you can
turn with your rig. Never allow safety chains to drag on
the ground.
Trailer Brakes
If your trailer weighs more than 2,000 Ibs. (900 kg)
loaded, then it needs its
own brakes - and they must be
adequate. Be sure
to read and follow the instructions
for the trailer brakes
so you’ll be able to install,
adjust and maintain them properly.
Since your vehicle is equipped with the
Stabilitrak@system, your trailer brake system cannot tap
into the vehicle’s hydraulic brake system.
4-52

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
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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.
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