1999 GMC C-SERIES steering wheel

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2-12 Fast Idle System (Electronically Controlled
Caterpillar

Diesel and Gasoline Engines)
If your vehicle is equipped with an electronically
controlled diesel engine, it has both automatic and
manual fast idle capabilities.
Automatic Fast Idle System
(Caterpillar

Diesel Engine Only)
The automatic fast idle feature will engage whenever
you start your vehicle and the engine is below the preset
operating temperature. This will help decrease engine
warm
-up time.
Idle speed will then return to normal under any of the
following conditions:

The engine reaches the preset operating temperature.

The brake pedal is pressed.

The trailer brake hand lever (if equipped) is applied.

The manual transmission clutch pedal is pressed or,
the automatic transmission (if equipped) is shifted
from NEUTRAL (N) or PARK (P).

The vehicle speed exceeds approximately
10 mph (16 km/h).

When the fast idle switch is pressed a second time.Manual Fast Idle System
(Caterpillar
 Diesel and Gasoline Engines)
The manual fast idle switch
is located on the lower
portion of the instrument
panel just to the left of the
steering wheel.
This system can be used to increase your engine idle
speed whenever the following conditions are met:

The brake pedal is not pressed.

The trailer brake hand lever (if equipped) is not applied.

The vehicle speed is below approximately
10 mph (16km/h).

The manual transmission (if equipped) clutch pedal
is not pressed or, the automatic transmission
(if equipped) is in NEUTRAL (N).
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2-31 Power Windows (If Equipped)
If you have power windows, the controls are on each
door. The driver's door has a switch for the passenger's
window as well. Your power windows will not move
unless the ignition switch is turned to RUN.
Push the switch marked with an up arrow to raise the
window. Push the switch marked with a down arrow to
lower the window.
Horn
Sound the horn by pushing the center of the steering
wheel. If you have the optional air horn, it is controlled
by a cord that you'll find up above and to the left of the
driver. The harder you pull on the cord, the louder the
air horn will sound. The air horn works only after your
air system pressure gets up to about 60 psi (415 kPa).
Tilt Wheel (If Equipped)
A tilt steering wheel allows you to adjust the steering
wheel before you drive. You can also raise it to the
highest level to give your legs more room when you
enter or exit the vehicle.
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2-32
To tilt the wheel, hold the steering wheel and pull the
lever. Move the steering wheel to a comfortable level,
then release the lever to lock the wheel in place.
Turn Signal/Multifunction Lever
The lever on the left side of the steering column
includes your:

Turn Signal and Lane Change Indicator

Headlamp High/Low Beam Changer

Windshield Wipers

Windshield Washer

Cruise Control (If Equipped)
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2-42
Let up on the accelerator before you turn on your rear
axle differential lock.
NOTICE:
Activating the rear-axle differential lock when
the rear wheels are actually spinning freely, as
they might on ice or snow, can cause you to lose
control of the vehicle. It can also damage the axle.
Turn on this control only when the wheels are not
spinning freely.
Engine Air Control (If Equipped)
If your vehicle has this control, the handle is located on
the instrument panel just to the right of the steering
wheel. The control is activated by pulling the handle out
and turning slightly in either direction to lock it.
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2-69 Transmission Temperature Gage
(If Equipped)
If you have an automatic
transmission and this gage,
it is to the right of the dash
mounted shift lever, just to
the right of your
floor
-mounted shift lever or
on the lower portion of the
instrument panel to the right
of the steering wheel.
When your ignition is on, the gage shows the
temperature of the transmission oil. A reading in the
warning zone means you must stop driving and check
into the cause. One possible cause is a low oil level in
the transmission.
NOTICE:
If you drive when the transmission temperature
gage is in the warning zone, you can badly
damage the transmission.
Air Pressure Gage (If Equipped)
If your vehicle has air
brakes, this gage at the
center of your instrument
cluster shows the air
pressure for both your front
and rear brake systems.
If the needle on the gage indicates that the air pressure is
below 60 psi (415 kPa), the LOW AIR warning light
will come on. An alarm will also sound if this happens.
The yellow pointer shows the pressure available for the
front system, while the green pointer shows pressure for
the rear. There should be no more than 4 psi (28 kPa)
difference showing between the systems.
Don't drive until both pointers are showing at least
120 psi (830 kPa), so you'll have enough air if you need
to apply your brakes.
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4-7
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. If you keep pace
with the traffic and allow realistic following distances,
you will eliminate a lot of unnecessary braking. That
means better braking and longer brake life.
If your engine ever stops while you're driving, brake
normally but don't pump your brakes. If you do, the
pedal may get harder to push down. If your engine
stops, you will still have some power brake assist. But
you will use it when you brake. Once the power assist is
used up, it may take longer to stop and the brake pedal
will be harder to push.
Hydraulic Brake Systems
If your engine stops running, or if your primary brake
system stops working, your vehicle has a reserve power
assist system to help you slow down. Just slowly and
steadily apply the brake pedal until you can safely get
off the road. The pedal will seem harder to push down.
Don't pump the pedal; the system won't work well or at
all that way.You may find that the steering wheel seems hard to turn
when you're turning and braking at the same time. Also,
the PRIMARY BRAKE warning light may come on and
the warning tone may sound. This is normal because the
main hydraulic brake system and power steering both
use the power steering pump. If this ever happens, let up
on the brake pedal a little. When you let up on the brake
pedal in that situation, it lets the steering get a little
more help from the pump.
Anti-Lock Brakes (Option)
Your vehicle may have anti-lock brakes (ABS). ABS is
an advanced electronic braking system that will help
prevent a braking skid.
If your vehicle has anti-lock
brakes, this warning light on
the instrument panel will
come on briefly when you
start your vehicle.
When you start your engine and begin to drive away,
your anti
-lock brake system will check itself. You may
hear a momentary motor or clicking noise while this test
is going on. This is normal.
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4-9
As you brake, your computer keeps receiving updates on
wheel speed and controls braking pressure accordingly.
Remember: Anti
-lock doesn't change the time you need
to get your foot up to the brake pedal or always decrease
stopping distance. If you get too close to the vehicle in
front of you, you won't have time to apply your brakes
if that vehicle suddenly slows or stops. Always leave
enough room up ahead to stop, even though you have
anti
-lock brakes.
Using Anti
-Lock
Don't pump the brakes. Just hold the brake pedal down
firmly and let anti
-lock work for you. You may feel the
brakes pulsate, or you may hear air exhausting, but this
is normal.
Braking in Emergencies
At some time, nearly every driver gets into a situation
that requires hard braking.
If you have anti
-lock, you can steer and brake at the
same time. However, if you don't have anti
-lock, your
first reaction
-- to hit the brake pedal hard and hold it
down
-- may be the wrong thing to do. Your wheels can
stop rolling. Once they do, the vehicle can't respond to
your steering. Momentum will carry it in whatever
direction it was headed when the wheels stopped rolling.That could be off the road, into the very thing you were
trying to avoid, or into traffic.
If you don't have anti
-lock, use a ªsqueezeº braking
technique. This will give you maximum braking while
maintaining steering control. You do this by pushing on
the brake pedal with steadily increasing pressure.
In an emergency, you will probably want to squeeze the
brakes hard without locking the wheels. If you hear or
feel the wheels sliding, ease off the brake pedal. This
will help you retain steering control. (If you do have
anti
-lock, it's different: see ªAnti-Lock Brakesº in
the Index.)
In many emergencies, steering can help you more than
even the very best braking.
Steering
Power Steering
If you lose power steering assist because the engine
stops or the system is not functioning, you can steer but
it will take much more effort.
On vehicles with hydraulic brakes, the power steering
and main hydraulic brake system both use the power
steering pump. See ªHydraulic Brake Systemsº in
the Index.
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4-10 Steering Tips
Driving on Curves
It's important to take curves at a reasonable speed.
A lot of the ªdriver lost controlº 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 the
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 suddenly apply the brakes. Both control
systems
-- steering and braking -- have to do their
work where the tires meet the road. Unless you have
four
-wheel anti-lock brakes, adding the hard braking
can demand too much of 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? Ease 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.
This is especially important with a tractor
-trailer. Try to
adjust your speed so you can ªdriveº 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.
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