1999 GMC C-SERIES instrument panel

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Then something will stop them. It could be
the windshield.Or it could be the instrument panel.
Now, what if you and your passengers were to give that
big vehicle a chance to deal with the force of the impact,
instead of you?
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2-
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Section 2 Features and Controls
Here you can learn about the many standard and optional features on your vehicle, and information on starting,
shifting and braking. Also explained are the instrument panel and the warning systems that tell you if everything is
working properly
-- and what to do if you have a problem.
2
-2 Keys
2
-4 Door Locks
2
-5 Theft
2
-5 New Vehicle ªBreak-Inº
2
-6 Ignition Positions
2
-7 Starting Your Gasoline Engine
2
-10 Starting Your Diesel Engine
2
-13 Engine Checks Before Operating
2
-15 Engine Coolant Heater (If Equipped)
2
-16 Diesel Engine Exhaust Brake
2
-17 Two-Speed Rear Axle Electric Shift Control
(If Equipped)
2
-20 Automatic Transmission Operation
2
-22 Manual Transmission Operation
2
-23 Parking
2
-29 Parking Over Things That Burn
2
-29 Engine Exhaust2
-30 Running Your Engine While You're Parked
(Automatic Transmission)
2
-30 Windows
2
-31 Tilt Wheel (If Equipped)
2
-32 Turn Signal/Multifunction Lever
2
-39 Trailer Brake Hand Control Valve (Option)
2
-40 Inter-Axle Differential Lock Control
(If Equipped)
2
-41 Rear Axle Differential Lock Control
(If Equipped)
2
-42 Engine Air Control (If Equipped)
2
-43 Exterior Lamps
2
-46 Interior Lamps
2
-46 Mirrors
2
-50 Instrument Panel
2
-52 Instrument Panel Cluster
2
-55 Warning Lights, Gages and Indicators
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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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The manual fast idle feature is activated by pressing the
switch on the instrument panel. When the switch is
pressed again, or any of the previous conditions are not
met, manual fast idle will be deactivated.
Manual fast idle can be used to set any desired idle
speed. To set a new temporary engine idle speed:
1. Make sure all of the previously described conditions
are met.
2. Press the accelerator pedal to the desired engine speed.
3. Momentarily press the manual FAST IDLE switch.
The temporary idle speed will be set. This new rpm
level will be remembered by the system until either the
ignition is turned to OFF or a new idle speed is set.
Radiator Shutters -- Caterpillar

(If Equipped)
Radiator shutters aid engine warm-up by blocking the
airflow through the radiator and charge the air cooler to
conserve heat in cold conditions.
The radiator shutters on your vehicle (if equipped)
operate automatically. When the ignition switch is in
RUN or START and the engine temperature is below
195F (90C), the shutters will close, blocking the flow
of air through the radiator and charge the air cooler.When the engine temperature reaches 195F (90C), the
shutters will open to the normal operating position.
Engine Checks Before Operating
When you've started your engine, let it run for 20 to
30 seconds before you put a load on the engine.
But don't leave the vehicle while the engine is running.
During this warm
-up period, check your warning lights
and gages:

If oil pressure doesn't begin to rise within 15 seconds
of starting, stop the engine and find the cause.

If the engine coolant temperature gage needle goes
into the hot area on the gage, stop the engine and
find the cause of the overheating.

If you have air brakes, the dual
-needle air pressure
gage should read at least 105 psi (720 kPa) for both
service systems before you try to move the vehicle.
When air pressure is below 60 psi (420 kPa), the
LOW AIR light will come on and you will hear a
tone alarm. If the pressure doesn't build up or drops
during warm
-up, stop the engine and find the cause
before you try to move the vehicle. Recommended
air pressure before actually driving away is
120 psi (830 kPa).
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4. Before starting the engine, be sure to unplug the cord.
How long should you keep the coolant heater plugged
in? The answer depends on the outside temperature.
Above 32
F (0
C), the coolant heater is not required.
From 32
F to
-10
F (0
C to -23
C), keep the
coolant heater plugged in at least two hours. Below
-10
F (-23
C), keep the coolant heater plugged in for
a minimum of eight hours or overnight. It will not harm
either the coolant heater or the vehicle to leave the
coolant heater plugged in longer than the times stated.
Be sure to remove and store the cord before starting the
engine. See ªDiesel Fuel Requirements and Fuel
Systemº in the Index for information on what fuel to use
in cold weather.
Diesel Engine Exhaust Brake
The exhaust brake is available on vehicles equipped
with a diesel engine and air brakes (or an air
compressor). It is located in the exhaust system.
The switch is on the upper
right side of the instrument
panel and turns the exhaust
brake on and off.
The exhaust brake indicator light is on when the exhaust
brake is in use.
The exhaust brake is used to help slow the vehicle and
may assist the vehicle's foundation brakes. The use of the
exhaust brake will assist the braking of the vehicle and
prolong the life of the foundation brake lining material.
When using the exhaust brake, the proper gear range
selection is important. The exhaust brake will be most
effective if the gear range selected is the lowest possible
range that does not allow the engine rpm to go more than
200 rpm above rated (full load) rpm as shown on the
Engine Information Plate. (Do not exceed 2900 rpm.)
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2-19 Air Shift Control
(Manual Transmissions Only)
The lever for the rear axle
shift control is either at the
lower right corner of the
instrument panel or on the
shift lever.
When the lever is moved to HI, the rear axle will be in
the high range. Switch it to LOW to get the low range.
The two
-speed axle should be in LOW when you park
the vehicle.
You'll need to engage the transmission, even moving the
vehicle a little, to be sure the axle is in the low range.
Then apply the parking brake, shift into NEUTRAL and
shut off the engine.Also, always start the vehicle in motion with the
two
-speed axle in the LOW position. When you upshift
the rear axle from LOW to HI, move the lever to the
HI position, disengage the clutch, pause, engage the
clutch and then press down on the accelerator. When
you shift the axle down from HI to LOW, you don't
have to clutch. Just move the lever to LOW, release the
accelerator and then quickly press it down again.
Air Suspension (If Equipped)
Your vehicle may be equipped with the Hendrickson
HAS Series single
-axle air suspension which is designed
for single
-axle on-highway use. This feature is available
in the 19,000 lb. capacity and as a low profile option for
operations which require extra cubic capacity and a
reduced deck height.
With this air suspension system, the ride height is set
during vehicle assembly so that the vehicle has a constant
frame height. The system will then increase or decrease
air pressure in the air springs to maintain this height.
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Air Suspension Dump Control (If Equipped)
If your vehicle is equipped with the Hendrickson HAS
Series single
-axle air suspension, you may have this
control. The air suspension dump control allows the
operator to lower the deck height approximately
4.5 inches (11.5 cm) from the normal frame height.
The switch to deflate and
inflate the air suspension is
located on the upper left
side of the instrument panel
above the driver's side vent.
The light in the switch will be illuminated whenever the
switch is in the ªdumpedº position.
Automatic Transmission Operation
We build vehicles with four, five and six-speed
automatic transmissions. This part of the manual covers
the basics of these. With some of the transmissions, you
will find another manual in your vehicle that goes into
more detail. On the ceiling, in front of and above the
driver, or in some other place near the driver, you will
see a label that describes important operating facts about
the automatic transmission in your vehicle. Make sure
you follow the instructions on this label.
You may have a PARK (P) position for your shift lever.
This position locks your rear wheels. It is the best
position to use when you start your engine because your
vehicle can't move easily.
All vehicles equipped with automatic transmissions
can be started in PARK (P), if equipped, or in
NEUTRAL (N). When you shift out of NEUTRAL (N),
you may have to hold in a push button on the shift lever
or lift up on a release handle as you shift. See the
Allison Automatic Transmission Operator's Manual in
your vehicle for more information about this.
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2-24 Hydraulic Brakes
If your vehicle has hydraulic brakes, it has a parking
brake lever or an electric/hydraulic parking brake. The
lever is below the instrument panel to the left of the
steering column. The electric/hydraulic parking brake
knob is to the right of the steering column.
Your vehicle may also be equipped with an automatic
transmission which has a shift lever. This lever will have
a PARK (P) position on the shift indicator. When the
PARK (P) position is selected with the shift lever, the
parking brake is automatically applied.
Propshaft Brake Burnish Procedure
It is recommended that the propshaft-mounted parking
brake be burnished as part of the new vehicle break
-in.
The parking brake will work best after it has been
burnished following these instructions.
Make 10 stops, using the parking brake hand lever, from
20 mph (32 km/h) about 2 1/2 miles (4 km) apart.
Between stops, drive the vehicle at 20 mph (32 km/h).
Lever Operated Parking Brake
To apply the parking brake,
pull the lever all the way up.
The PARK BRAKE light
will come on when the
parking brake is applied.
Then shift the transmission
to NEUTRAL (N) or
PARK (P).
The vehicle must be stopped when applying the parking
brake, except while burnishing the parking brake linings
(see ªPropshaft Brake Burnish Procedureº in the Index).
You can easily adjust the parking brake by turning the
knob on the lever. Turning it clockwise makes the brake
grip more tightly. It will also make the lever seem harder
to pull up. Turning the knob counterclockwise makes the
parking brake apply less firmly. Adjust the parking
brake only when the lever is down (released).
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