light GMC SIERRA 1993 Workshop Manual

Most drivers treat their brakes with care. Some, however, overw\
ork the
braking system with poor driving habits.
Avoid needless heavy braking. Some people drive in spurts-heavy
acceleration followed by heavy braking-rather than keeping pace with
traffic. This is
a mistake. Your brakes may not have time to cool
between hard stops. Your brakes will wear out much faster
if you do a
lot of heavy braking.
Don’t “ride” the brakes by letting your left foot rest\
lightly on the brake
pedal while driving.
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AM410001
CAUTION I
1 “Riding” your brakes can cause them to overheat to the point that
- they won’t work well. You might not be able to stop your vehicle in
time to avoid an accident. If you “ride” your brakes, they will get
so
hot they will require a lot of pedal force to slow you down. Avoid
“riding” the brakes.
NOTICE
“Riding” the brakes wears them out much faster. You would need costly
brake replacement much sooner than normal. and it also reduces fuel
economv.
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Your Driving and fhe Road
Brake System Warning Light
K2325
This light appears on your instrument cluster to warn you if your regular
braking’ system needs service. See “Brake System Warning L\
ight” in the
Index.
Disc Brake Wear Indicators
If you have a C 3500 HD Model, it has four-wheel disc brakes. Disc brake
pads have built-in wear indicators that make a high-pitched war\
ning sound
when the brake pads are worn and new pads are needed. The so\
und m’ay
come and go or be heard all the time your vehicle is moving (except \
when
you are pushing on the brake pedal firmly).
1 CAUTION
The brake wear warning sound means that sooner or later your
hear the brake wear warning sound, have your vehicle serviced. \
5 brakes won’t work well. That could lead to an accident. When you I ~
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i
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brakes are first applied or lightly applied. This does not mea\
n something is
wrong with your brakes.
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Your Driving and the Road
Steering Tips Driving
on Curves
It’s important to take curves at a reasonable speed.
A lot of the “driver lost control” accidents mentioned on the news \
happen on
curves. Here’s why:
Experienced driver or beginner, each of us is subject to the same laws
of
physics when driving on curves. The traction of the tires against the road
surface makes it possible for the vehicle to change its path when you turn
the front wheels.
If there’s no traction, inertia will keep the vehicle going in
the same direction.
If you’ve ever tried to steer a vehicle on wet ice, you’ll
understand this.
The traction you can get in a curve depends on me condition of your tires
and the road surface, the angle at which the curve is banked,\
and your
speed. While you’re in a curve, speed is the one factor you can control.
Suppose you’re steering through a sharp curve. Then you sudd\
enly apply the
brakes. Both control systems-steering and braking-have to
do their work
where the tires meet the road. Adding the hard braking can de\
mand too
much at those places. You can lose control.
The same thing can happen
if you’re steering through a sharp curve and you
suddenly accelerate. Those two control systems-steering and
acceleration-can overwhelm those places where the tires meet the road and
make you lose control.
What should you
do if this ever happens? Let up on the brake or accelerator
pedal, steer the vehicle the way you want it to
go, and slow down.
Speed limit signs near curves warn that you should adjust your\
speed. Of
course, the posted speeds are based on
good weather and road conditions.
Under less favorable conditions you’ll want to go slower.
If you need to reduce your speed as you approach a curve, do it before you
enter the curve, while your front wheels are straight ahead.
Try to adjust your speed
so you can “drive” through the curve. Maintain a
reasonable, steady speed. Wait to accelerate until you are out of the curve,
and then accelerate gently into the straightaway.
When you drive into a curve at night, it’s harder
to see the road ahead of
you because it bends away from the straight beams
of your lights. This is
one good reason to drive slower.
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Your Drivm - and the Road.
Off-Road Recovery
You may find. sometime that your right wheels have dropped off the edge of
a road onto the shoulder while you're driving.
If the level of the shoulder is only slightly below the pavement, recovery
should be fairly easy. Ease
off the accelerator and then, if there is nothing in
the way, steer
'so that your vehicle straddles the edge of the pavement. You
can turn the steering wheel up to
1/4 turn until the right front tire contacts
the pavement edge. Then turn your steering wheel to go straight down the
roadway.
AM428003
If the shoulder appears to be about four inches (100 mm) or more below the
pavement, this difference can .cause problems.
If there is not enough room to
pull entirely onto the shoulder and stop, then follow the same proc\
edures. But
if the right front tire scrubs against the side of the pavement, do NOT steer
more sharply. With
too much steering angle, the vehicle may jump back onto
the road with
so much steering input that it crosses over .into the oncoming
traffic before you can bring
it back under control.
Instead, ease off again on the accelerator and steering input, \
straddle the
pavement once more, then
try again.
Passing
The driver of a vehicle about to pass another on a two-lane highway waits
for just the right moment, accelerates, moves around the vehicl\
e ahead, then
goes back into the right lane again.
A simple maneuver?
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Your Driving and the Road
the right lane. (Remember that your right outside mirror is c\
onvex. The
vehicle you just passed may seem to be farther away from you \
than
it
really is).
Try not to pass more than one vehicle at a time on two-lane roads.
Don’t overtake a slowly moving vehicle too rapidly. Even though the
Reconsider before passing the next vehicle.
brake lights are not flashing, it may be slowing down
or starting to turn.
If you’re being passed, make it easy for the following driver to get ahead
of you. Perhaps you can ease a little
to the right.
Loss of Control
Let’s review what driving experts say about what happens whe\
n the three
control systems (brakes, steering and acceleration) don’t ha\
ve enough friction
where the tires meet the road to do what the driver has asked.
In any emergency, don’t give up. Keep trying to steel+-, arid constantly seek an
escape route
or area of less danger.
Skidding
In a skid, a driver can lose control of the vehicle. Defensive drivers avoid
most skids by taking reasonable care suited
to existing conditions, and by not
“overdriving” those conditions. But skids are always possib\
le.
The three types
of skids correspond to your vehicle’s three control systems.
In the braking skid your wheels aren’t rolling. In the steering
or cornering
skid, too much speed
or steering in a curve causes tires to slip and lose
cornering force. And in the acceleration skid too much throttle\
causes the
driving wheels to spin.
A cornering skid and an acceleration skid are best handled by ea\
sing your
foot
off the accelerator pedal. If your vehicle starts to slide (as when you turn
a corner on a wet, snow-
or ice-covered road), ease your foot off the
accelerator pedal as soon as you feel the vehicle start to sl\
ide. Quickly steer
the way you want the vehicle
to go. If you start steering quickly enough, your
vehicle
will straighten out. As it does, straighten the front wheels.
Of course, traction is reduced when water, snow, ice, gravel, or other material
is on the road.
For safety, you’ll want to slow down and adjust your driving to
these conditions. It is important to slow down on slippery surfaces because
stopping distance will be longer and vehicle control more limit\
ed.
While driving on a surface with reduced traction,
try your best to avoid
sudden steering, acceleration,
or braking (including engine braking by shifting
to a lower gear). Any sudden changes could cause the tires to slid\
e. You
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Your Driving and the Road
Does the travel take you uphill or downhill? (There’s more \
discussion of
Will you have to stop suddenly or change direction quickly? these subjects later.)
When you drive over obstacles
or rough terrain, keep a firm grip on the
steering wheel. Ruts, troughs, or other surface features can jerk the wheel
out of your hands
if you’re not prepared.
When you drive over bumps, rocks, or other obstacles, your whe\
els can leave
the ground.
If this happens, even with one or two wheels, you can’t contro\
l
the vehicle as well
or at all.
Because you will be on an unpaved surface, it’s especially \
important
to avoid
sudden acceleration, sudden turns,
or sudden braking.
In a way, off-road driving requires a different kind of alertness from driving on
paved roads and highways. There are no road signs, posted spee\
d limits
or
signal lights. You have to use your own good judgment about what is safe
and what isn’t.
* Drinking and driving can be very dangerous on any road. And this is I
1 certainly true for off-road driving. At the very time you need special
alertness and driving skills, your reflexes, perceptions and jud\
gment
can be affected by even a small amount of alcohol. You could have
a serious-or even fatal-accident
if you drink and drive or ride with
a driver who has been drinking. (See “Drunken Driving”
in the
Index.)
Driving On Off-Road Hills
Off-road driving often takes you up, down, or across a hill. Driving safely on
hills requires good judgment and an understanding of what your vehicle can
and can’t do. There are some hills that simply can’t be \
driven, no matter how
well built the vehicle.
A, Many hills are simply too steep for any vehicle. If you drive up them,
- IOU will stall. If you drive down them, you can’t control your speed. If
you drive across them, you will roll over. You could be seriously
injured or killed.
If you have any doubt about the steepness, don’t
drive the hill.
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Your Driving and the Road
A Turning or driving across steep hills can be dangerous. You could
lose traction, slide sideways, and possibly roll over. You could be
seriously injured or
I 'I' ?d. When driving up hills, always try to go
I straight up.
Ease up on your speed as you approach the top of the hill.
Attach a flag to the vehicle to make you more visible to approaching
traffic on trails or hills.
Sound the horn as you approach the top of hill to let opposing traffic
know you're there.
Use your headlights even during the day. They make you more visible to
oncoming traffic.
I A Driving to the top (crest) of a hill at full speed can muse an
accident.
There could be a drop-off, embankment, cliff, or even
another vehicle. You buld be seriously injured or killed. .As you near
the
top of a hill, slow down and stay alert. I
Q: What should I do if my vehicle stalls, or is about to stall, and I can't
make it
up the hill?
A: If this happens, there are some things you should do, and there are some
things
you must not do. First, here's what you should do:
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0
Push the brake pedal to stop the vehicle and keep it from rolling
backwards.
Also, apply the parking brake.
If your engine is still running, shift the transmission into reverse, release
the parking brake, and slowly back down the hill in reverse.
If your engine has stopped running, you'll need to restart it. With the
brake pedal depressed and the parking brake still applied, shift the
transmission to
P (Park) (or, shift to N (Neutral) if your vehicle has a
manual transmission) and restart the engine. Then, shift to Reverse,
release the parking brake, and slowly back down the hill in reverse.
As you are backing down the hill, put your left hand on the ste\
ering
wheel at the
12 o'clock position. This way, you'll be able to tell if your
wheels are straight or turned to the left or right as you back down.
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Your Driving and the Road
If you decide you can go down a hill safely, then try to keep your vehicle
headed straight down, and use a low gear. This way, engine dr\
ag can help
your brakes and they won’t have to do
all the work. Descend slowly, keeping
your vehicle under control at all times.
CAUTION
A Heavy braking when going down a hill can cause your brakes to
overheat and fade. This could cause
loss of control and a serious ‘
accident. Apply the brakes lightly when descending a hill and use a
low gear to keep vehicle speed under
control.
Q: Are there some things I should not do when driving down a hili?
A: Yes! These are important because if you ignore them you could lose
control and have a serious accident.
When driving downhill, avoid turns that take you across the in\
cline of the
hill.
A hill that’s not too steep to drive down may be too steep to drive
across. You could
roll over if you don’t drive straight down.
Never go downhill with the transmission in N (Neutral), or with the clutch
pedal depressed in a manual shift. This is called “free-whee\
ling,” Your
brakes will have
to do all the work and could overheat and fade.
Avoid braking so hard that you lock the wheels when going downhill. If
your front wheels are locked, you can’t steer your vehicle. \
If your wheels
lock up during downhill braking, you may feel the vehicle star\
ting to slide
sideways.
To regain your direction, just ease off the brakes and steer to
keep the front of the vehicle pointing straight downhill.
Q: Am I likely to stall when going downhill?
A: It’s much more likely to happen going uphill. But if it happens going
downhill, here’s what to do.
Stop your vehicle by applying the regular brakes. Apply the pa\
rking
brake.
Shift to P (Park) (or to Neutral with the manual transmission) and, while
still braking, restart the engine.
Shift back to a low gear, release the parking brake, and drive straight
down.
If the engine won’t start, get out and get help.
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has an effect on steering, accelerating, and braking. You may want to reduce
the air pressure in your tires slightly when driving on sand. \
This will improve
traction.
Hard packed snow and ice offer the worst tire traction. On th\
ese surfaces, it’s
very easy to lose control. On wet ice, for example, the tract\
ion
is so poor
that you will have difficulty accelerating. And
if you do get moving, poor
steering and difficult braking can cause you to slide out of control.
I A Driving on frozen lakes, ponds or rivers can be dangerous. I
Underwater springs, currents under the ice, or sudden thaws can
weaken the ice. Your vehicle could fall through the ice and you and
your passengers could drown. Drive your vehicle on
safe surfaces
on
I y.
.
Driving In Water
Light rain causes no special off-road driving problems. But hea\
vy rain can
mean flash flooding, and flood waters demand extreme caution.
Find out how deep the water is before you drive through
it. If it’s deep
enough to cover your wheel hubs, axles, or exhaust pipe, don’\
t try it-you
probably won’t get through. Also, water that deep can damage\
your axle and
other vehicle parts.
If the water isn’t too deep, then drive through it slowly. At fast speeds, water
splashes on your ignition system and your vehicle can stall. S\
talling can also
occur
if you get your tailpipe under water. And, as long as your tailp\
ipe is
under water, you’ll never be able to start your engine. Whe\
n you go through
water, remember that when your brakes get wet, it may take you longer to
stop.
Driving through rushing water can be dangerous. Deep water can \
sweep your vehicle downstream and you and your passengers could\

drown.
If it’s only inches deep, it can still wash away the ground
from under your tires, and you could lose traction and roll t\
he vehicle
over. Don’t drive throuah rushina water. I
If you have a diesel engine, see “Driving Through Water (Diese\
l Engines)” in
the Index for more information on driving through water.
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Your Driving and the Road
After Off-Road Driving
Remove any brush or debris that has collected on the underbody\
, chassis, or
under the hood. These accumulations can be a fire hazard.
After operation in mud or sand, have the brake linings cleaned\
and checked. These substances can cause glazing and uneven braking. Check th\
e body
structure, steering, suspension, wheels, tires, and exhaust syste\
m for damage.
Also, check the fuel lines and cooling system for any leakage.
Your vehicle will require more frequent service due
to off-road use. Refer to
Section
7 for additional information.
Driving at Night
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Night driving is more dangerous than day driving. One reason is that some
drivers are likely
to be impaired-by alcohol or drugs, with night vision
problems, or by fatigue.
Here are some tips on night driving.
Drive defensively. Remember, this is the most dangerous time.
Don’t drink and drive (See “Drunken Driving” in the Index for more on
this problem).
Adjust your inside rear view mirror to reduce the glare from headlights
Since you can’t see as well, you may need to slow down and keep
behind
you.
more space between you and other vehicles. It’s hard
to tell how fast
the vehicle ahead is going just
by looking at its taillights.
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