1999 GMC C-SERIES window

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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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2-35
Low Speed Delay Wipers (If Equipped)
You can set the wiper speed
for a long or short delay
between wipes. This can be
very useful in light rain or
snow. Turn the band to
choose the delay time.
The closer to LO, the
shorter the delay.
Heavy snow or ice can overload your wipers. Clear
away snow or ice to prevent bending or breaking the
wiper linkage.
Windshield Washer
At the top of the multifunction lever, there's a paddle
with the word PUSH on it. To spray washer fluid on the
windshield, push the paddle.
CAUTION:
In freezing weather, don't use your washer until
the windshield is warmed. Otherwise the washer
fluid can form ice on the windshield, blocking
your vision.
If you have the standard wipers, the wipers will keep
going in LO until you turn the wiper control to the
off symbol.
If you have the low
-speed delay option, the wipers will
clear the window and then either stop or return to your
preset speed.
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2-51
A. Left Side Window Defogger
B. Main Lamps Switch
C. Vent
D. Instrument Cluster
E. Warning Lights
F. Heated Mirror Switch (Option)
G. Exhaust Brake Switch (Option)
H. Marker/Clearance Lamps Switch (Option)
I. Audio System or Storage Area
J. VentsK. Glove Box
L. Right Side Window Defogger
M. Storage Tray/Cassette Player
N. Comfort Controls
O. Air Brake Controls (If Equipped)
P. Ashtray
Q. Air Vent Controls
R. Convenience Center Fuse Panel
S. Hourmeter (Option)
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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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3-4
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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3-6 Defogging
Use DEFOG, along with the HEATER setting, when
there is fog or ice on the windshield. This will direct
airflow toward the windshield and front side windows.
Set the temperature selector toward H and the fan
control at a comfortable level. When the windshield is
clear, use the temperature selector bar and the fan
control button to maintain a comfortable
temperature level.
Ventilation System
Air comes into your vehicle in one of two ways: power air
or ram air. Power air means bringing outside air into the
cab through the air intake, using the blower fan. Fresh air
can be drawn in when the vehicle is stationary or moving
at low speed. Air comes in through four vents in the
instrument panel and is exhausted through the vents and
pressure relief valves in the doors and door pillars. Power
ventilation means an increased supply of fresh air is
brought into the cab interior without having to open the
windows, especially during inclement weather.
Ram air is forced into the cab through the air intake in
the cowl by the vehicle's forward motion. This air is
controlled by two vent air handles under the instrument
panel. Air is directed through the ventilation ducts to the
floor. Ram air provides good airflow into the cab at
normal road speeds.
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3-7
Ventilation Tips

Keep the hood and front air inlet free of ice, snow or
any other obstruction (such as leaves). The heater
and defogger will work far better, reducing the
chance of fogging the inside of your windows.

When you enter a vehicle in cold weather, turn the
blower fan to high for a few moments before driving
off. This helps clear the intake ducts of snow and
moisture and reduces the chance of fogging the
inside of your windows.

Keep the air path under the seats clear of objects.
This helps air to circulate throughout your vehicle.
The air vents are located in the center and on the sides of
your instrument panel. You can move the vents to direct
the flow of air or close the vents altogether. When you
close a vent, it will increase the flow of air coming out
of any vents that are open.
If your vehicle does not have air conditioning, there are
air vent controls located below the instrument panel.Audio Systems
Your Delco Electronics audio system has been designed
to operate easily and give years of listening pleasure.
You will get the most enjoyment out of it if you acquaint
yourself with it first. Find out what your Delco
Electronics system can do and how to operate all its
controls, to be sure you're getting the most out of the
advanced engineering that went into it.
Setting the Clock
While pressing the SET button, press the UP button
until the correct hour appears on the display and the
DOWN button until the correct minute appears on the
display. If you press and hold the UP/DOWN button,
hours or minutes will advance rapidly.
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