air condition GMC C-SERIES 1999 Owners Manual

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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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2-21
CAUTION:
It is dangerous to get out of your vehicle if the
shift lever is not fully in PARK (P) with the
parking brake firmly set. Your vehicle can roll.
Don't leave your vehicle when the engine is
running unless you have to. If you have left the
engine running, the vehicle can move suddenly.
You or others could be injured. To be sure your
vehicle won't move, even when you're on fairly
level ground, always set your parking brake and
move the shift lever to PARK (P).
See ªShifting Into PARK (P)º in the Index.
CAUTION:
Shifting out of PARK (P) or NEUTRAL (N) while
your engine is ªracingº (running at high speed) is
dangerous. Unless your foot is firmly on the
brake pedal, your vehicle could move very
rapidly. You could lose control and hit people or
objects. Don't shift out of PARK (P) or
NEUTRAL (N) while your engine is racing.
Automatic Transmission Third Gear Hold
(If Equipped)
If you have this feature, your range selector has a
ª2
-3º position. You can't shift up to the next higher
gear when the transmission is in this position unless
your engine
-governed speed is exceeded, such as when
going downhill.
This feature is useful for certain load and traffic
conditions or when plowing snow. See the Allison
Automatic Transmission Operator's Manual in your
vehicle for further information.
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2-57
Readings in the low warning zone may occur when a
large number of electrical accessories are operating
in the vehicle and the engine is left at an idle for an
extended period. This condition is normal since the
charging system may not be able to provide full
power at engine idle. As engine speeds are increased,
this condition should correct itself because higher
engine speeds allow the charging system to create
maximum power.
You can only drive a short time on the battery. Be sure
to shut off the radio, the fan or any unnecessary
accessories and have the system serviced.
Do Not Shift Warning Light
If your vehicle has the
Allison MD automatic
transmission, certain
transmission malfunctions
will turn this light on.If this light comes on while you are driving, do not use
the transmission shift control. Using the transmission
shift control will result in the loss of forward gears. The
computer for the transmission senses a problem and
chooses a gear to stay in so that you can drive the
vehicle in that gear. You may not be able to drive as fast
or back up when this light is on.
NOTICE:
If the DO NOT SHIFT warning light comes on
while you are driving, it is a warning that making
a transmission ªrangeº change could leave you
stranded. The vehicle may not continue to move
if you change gears with the transmission shift
control. The transmission can't operate in all
gears because something is wrong. Leave the shift
control alone and drive directly to a GM dealer
for service. If you can't go in for service
immediately, have the vehicle towed.
Brake System Warning Light
Your vehicle has either hydraulic or air brakes. Each
system has different warning lights.
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2-60 Apply Park Brake Warning Light (Option)
This light warns the driver
that the ignition has been
turned off without applying
the parking brake. The
warning light should come
on, as a check, when you
start the engine.
When it comes on, you will also hear a warning tone.
Leaving the vehicle in this condition could result in your
vehicle moving and will discharge the battery.
Parking Brake Warning Light
This light turns on as a
check when the engine is
first started and any time the
system needs adjustment or
there is a malfunction in the
electric/hydraulic parking
brake system.
When the SERVICE PARK BRAKE light comes on,
you will also hear a warning tone. If this light comes on,
have the system repaired immediately.
CAUTION:
If the SERVICE PARK BRAKE warning light
comes on and the warning tone sounds, your
vehicle can stop suddenly and without further
warning. You or others could be injured. If the
SERVICE PARK BRAKE warning light and the
warning tone come on, pull over to the side of the
road and apply the parking brake immediately.
Parking Brake Indicator Light
Vehicles with hydraulic or
air brakes have a parking
brake indicator light. When
the ignition is on, this light
will come on when you set
your parking brake.
The light will stay on if your parking brake doesn't
release fully.
This light should also come on when you turn the
ignition key to START. If it doesn't come on then, have
it fixed so it will be ready to remind you if the parking
brake is applied or hasn't released fully.
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3-
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3-1
Section 3 Comfort Controls and Audio Systems
In this section, you'll find out how to operate the comfort control and audio systems offered with your vehicle.
Be sure to read about the particular systems supplied with your vehicle.
3
-2 Comfort Controls
3
-5 Air Conditioning
3
-5 Heating
3
-6 Defogging
3
-6 Ventilation System
3
-7 Audio Systems
3
-7 Setting the Clock3
-8 AM/FM Stereo
3
-10 Remote Cassette Tape Player (If Equipped)
3
-10 Understanding Radio Reception
3
-11 Tips About Your Audio System
3
-12 Care of Your Cassette Tape Player
3
-12 Fixed Mast Antenna
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3-2
Comfort Controls
Standard Comfort Controls
If your vehicle does not have air conditioning, this is
what your comfort controls will look like.
Function Lever
The top lever can be moved to three different heating
functions. If you place the lever between positions, it
will send air out both vents.
VENT: The air comes out at the vents on your
instrument panel and at your front side windows.
HEATER: Heated air comes out near the floor.
This is the best setting for cold weather.
DEFOG: This setting operates the defogger.
Heated air comes out near the windshield. Use this when
fog or ice is on the windshield.
Temperature Lever
The bottom lever lets you select the temperature of the
air flowing into your vehicle. Move the lever to the plus
symbol for warmer air. Move the lever to the minus
symbol for cooler air.
If your engine is equipped with an engine coolant heater,
you can use it during initial start
-up in cold weather
(20
F (
-8
C) or lower) to help heat the passenger
compartment faster. See ªEngine Coolant Heaterº in
the Index.
Fan Knob
The fan knob has four positions. To increase airflow,
turn the knob toward the plus symbol. To decrease
airflow, turn it toward the minus symbol.
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3-3 Optional Comfort Controls (If Equipped)
If your vehicle has air conditioning, your comfort
controls will look like this.
Your system has a lighted display showing each system
when it is operating. During normal operation, all the
lights won't come on at the same time. Only the ones
displaying the current settings will light.
Temperature Selector Bar
The bar under your system display lets you select the
temperature of the air coming into the passenger area of
your vehicle. Press COLD for cooler air and press HOT
for warmer air. Release the bar when the system reaches
the temperature you want. The temperature is shown on
the display by an arrow moving between C and H.
If your engine is equipped with an engine coolant heater,
you can use it during initial start
-up in cold weather
(20
F (
-8
C) or lower) to help heat the passenger
compartment faster. See ªEngine Coolant Heaterº in
the Index.
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Left Blend Button
The airflow can be blended between the two positions.
To blend between the positions, press the side of the
button showing the area where you would like more
airflow. The system will automatically begin to blend
toward the position chosen. To stop the system between
positions, just press the same side of the button again.
VENT: Press the top of the button and all of the
airflow will come through the instrument panel vents.
HEATER: Press the bottom of this button and all
of the airflow will come through the floor outlet.
Right Blend Button
The airflow can be blended between the two positions.
To blend between positions, press the side of the button
showing the area where you would like more airflow.
The system will automatically begin to blend toward the
position chosen. To stop the system between positions,
just press the same side of the button again.
DEFOG: This setting operates the defogger. Air
comes out near the bottom of the windshield and at your
front side windows.
HEATER: Press the bottom of this button and
heated air comes out near the floor.A/C Button
Press the A/C button to turn your air conditioner on and
off. The A/C symbol will light on your display, and air
will come out of your instrument panel vents. The fan
will automatically be set on LOW.
MAX Button
If you press the MAX button, the air in your vehicle will
be recirculated. With the air conditioner on, MAX will
give you maximum cooling. It can also be used in all
modes to help keep dust out of your vehicle. When
MAX is selected, REC will light on the display.
Fan Control Button
This button is in the upper passenger's side corner of
your system control panel. The fan has four settings:
low, medium low, medium high and high. Press the top
of the button with the plus symbol to increase airflow.
Press the bottom of the button with the minus symbol to
decrease airflow. The setting you select is shown on
your display as LOW, MED, HI or OFF.
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3-5
OFF
Press this button to turn the air conditioning/heating
system off. Pressing OFF will erase the present mode of
operation from the system's memory. Outside air will
still come out of the heater outlet whenever the vehicle
is moving forward.
If the OFF button is pressed, you must press A/C,
MAX or one of the BLEND buttons to turn the system
back on.
Air Conditioning
When you first turn on your vehicle's air conditioning,
open the windows long enough to clear the vehicle of
hot air, then close them. Using the MAX button can also
help. See ªMAX Buttonº earlier in this section for
more information.
For normal cooling on hot days, use A/C with the
temperature selector toward C.
When you press the A/C button to turn the air
conditioner off, the system will operate in the vent
mode. When you turn the air conditioner back on, the
system will operate in the mode you last selected unless
the OFF button was pressed.If your air conditioner develops high system pressure, it
will automatically go into the MAX mode and REC will
light on your display. The A/C system will remain in the
MAX mode, even if you press the MAX button, until
system pressure returns to a normal level.
Heating
On cold days, use HEATER with the temperature
selector all the way toward H. When the inside of the
vehicle has reached a comfortable temperature, maintain
it by using the temperature selector bar.
If your vehicle is equipped with a diesel engine, and the
engine has been idling for a long time when it's cold
outside, your heater may blow out cool air. This is
normal. When you increase the engine speed under load,
your heater should blow out warmer air. If it doesn't,
your coolant level may be low. See ªEngine Coolantº in
the Index to check your coolant level.
While idling your diesel engine, you can use the MAX
button to recirculate the air in the cab to help maintain
interior heat. This will preserve engine coolant temperature
and cab heat when idling cannot be avoided.
Using the MAX button while driving is not recommended
because interior window fogging can result.
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