1999 GMC C-SERIES alarm

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2-11 Cold Weather Starting (Caterpillar

Diesel)
Because the diesel engine uses compression ignition, it
is harder to start in cold weather than a gasoline engine.
The air intake heater and use of the proper engine oil,
optional engine coolant heaters and optional ether
injection systems help cold weather starting. See the
Caterpillar

Operation & Maintenance Manual for
more information.
Diesel Engine Warm-Up
Several factors affect how quickly your diesel engine
warms up. These can include outside temperature,
engine load, idle time and your vehicle's option content.
Your vehicle may be equipped with some features that
can help the engine reach operating temperature sooner.
Some of these features are discussed below.
Also, remember that an automatic transmission adds
heat to the cooling system through the heat exchanger in
the radiator. Because of this, vehicles equipped with
automatic transmissions are often able to retain engine
coolant heat better than manual transmission vehicles.
See your Caterpillar

Operation & Maintenance manual
for additional diesel engine warm
-up information.
Engine Automatic Shutdown (If Equipped)
Your CHECK GAGES light will come on if the system
senses high engine temperature or low engine oil
pressure. If high engine temperature is detected, you
will also hear a tone alarm at two beats per second. The
alarm and the light will remain on until the condition is
fixed. If the engine temperature condition worsens, the
tone alarm will go to five beats per second. When a low
oil pressure condition is detected, the five beat per
second alarm will come on immediately.
If the system senses low engine coolant, the five beat
per second alarm and the LOW COOLANT warning
light will come on.
The five beats per second tone alarm means that your
engine will shut down in 25 seconds. Pull off the road
and shut off the engine. Don't start it until the reason for
the problem is known, and the problem is fixed. If the
engine shuts down when you are still in traffic, you can
restart the engine and get another 25 seconds of
operation. Do this only if you have to, since there is a
problem that can harm the engine if it isn't fixed.
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2-13
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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2-44
Press the top left switch to turn on your:

Parking Lamps

Marker Lamps (unless your vehicle has the optional
marker and clearance lamps switch)

Taillamps

Instrument Panel Lights

License Plate Lamps
Push the bottom left switch to turn on the headlamps, as
well as all of the lamps just listed. Push the switch
marked with the ªOº symbol to turn off your lamps.
Move the thumbwheel to the right of the off switch
down to dim your instrument panel lights. Moving this
wheel up makes these lights brighter. Moving it all the
way up will make the interior lamp come on.
A circuit breaker protects your headlamps. If you have
an electrical overload, your headlamps will flicker on
and off. Have your headlamp wiring checked right away
if this ever happens.Headlamps On Reminder (If Equipped)
If you have this system, a tone alarm will sound when
your headlamps and/or parking lamps are turned on and
your ignition is in OFF, LOCK or ACCESSORY.
Daytime Running Lamps (If Equipped)
Daytime Running Lamps (DRL) can make it easier for
others to see the front of your vehicle during the day.
DRL can be helpful in many different driving
conditions, but they can be especially helpful in the
short periods after dawn and before sunset.
The high and low
-beam headlamps will come on at
reduced brightness in daylight when:

The ignition is on,

The headlamp switch is off and

The parking brake is released.
When the DRL are on, only your low
-beam headlamps
will be on. The exterior lamps won't be on. Your
instrument panel won't be lit up either.
When it begins to get dark, your DRL indicator light is a
reminder to turn your headlamp switch on. The other
lamps that come on with your headlamps will also
come on.
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2-55
Warning Lights, Gages and Indicators
This part describes the warning lights and gages that
may be on your vehicle. The pictures will help you
locate them.
Warning lights and gages can signal that something is
wrong before it becomes serious enough to cause an
expensive repair or replacement. Paying attention to
your warning lights and gages could also save you or
others from injury.
Warning lights come on when there may be or is a
problem with one of your vehicle's functions. As you
will see in the details on the next few pages, some
warning lights come on briefly when you start the
engine just to let you know they're working. If you are
familiar with this section, you should not be alarmed
when this happens.
Gages can indicate when there may be or is a problem
with one of your vehicle's functions. Often gages and
warning lights work together to let you know when
there's a problem with your vehicle.When one of the warning lights comes on and stays on
when you are driving, or when one of the gages shows
there may be a problem, check the section that tells you
what to do about it. Please follow this manual's advice.
Waiting to do repairs can be costly
-- and even
dangerous. So please get to know your warning lights
and gages. They're a big help.
Safety Belt Reminder Light (Option)
When the key is turned to
RUN or START, a light will
come on for about eight
seconds to remind people
to fasten their safety belts.
Safety Belt Reminder Tone (Option)
When the key is turned to RUN or START, a tone will
sound for about eight seconds to remind people to fasten
their safety belts.
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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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6-70
Name Circuits Protected
HYD BRK Brake Pump Motor Relay
HYD BRK Brake Alarm ModuleName Circuits Protected
B/U IGN3 Fuel Filter Relay, Blower Motor
Relays, ABS Power Relay,
Back
-Up Lamps, Auxiliary Wiring
Relay, IGN 3 Relay, Power
Window Relay, Vehicle Interface
Module, Transmission
Temperature Gage
STOP Stoplamps
WASH/WIPE Windshield Wipers/Washer,
Accessory Relay
DOME/PNL Dome Lamp, Radio Receiver,
Instrument Panel Lights,
A/C Controller,
Headlamp/Seatbelt Module
BLOWER Blower Motor
A/C A/C Clutch Compressor,
A/C Controller
TRN/HAZ Turn Signals, Hazard Flashers
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7-25
Starter Switch Check
CAUTION:
When you are doing this check, the vehicle could
move suddenly. If it does, you or others could be
injured. Follow the steps below.
1. Before you start, be sure you have enough room
around the vehicle.
2. Firmly apply both the parking brake (see ªParking
Brakeº in the Index if necessary) and the
regular brakes.
NOTE: Do not use the accelerator pedal, and be
ready to turn off the engine immediately if it starts.
3. On automatic transmission vehicles, try to start the
engine in each gear. The starter should work only in
PARK (P), if equipped, or NEUTRAL (N). If the
starter works in any other position, your vehicle
needs service.Automatic Transmission Shift Indicator Check
Check that the indicator points to the gear chosen.
Steering Check
Be alert for any changes in steering action, abnormal
front tire wear or steering wheel position. An inspection
or service is needed when the steering wheel is harder to
turn or has too much free play, or if there are strange
sounds when turning or parking.
Brake System Check
Be alert to illumination of the low air warning lamp or
for the tone alarm, or changes in braking action, such as
repeated pulling to one side, unusual sounds when
braking or increased brake pedal travel. Make sure air
brake system reservoirs are drained daily with full
system air pressure, and check system for leaks. Any of
these conditions could indicate the need for brake
system inspection and/or service.
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