1999 BUICK CENTURY air conditioning

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Comfort Controls
Manual Single Zone Climate Control
With this system, you can control the heating, cooling
and ventilation in your vehicle. The system works best if
you keep your windows closed while using it.
Fan Knob
The left knob controls the amount of air you want. To
turn the fan off, turn the knob to OFF.
If the airflow seems very low when the fan knob is turned
to the highest setting, regardless of the mode setting, your
passenger compartment air filter may need to be replaced.
See ªMaintenance Scheduleº or ªPassenger Compartment
Air Filterº in the Index.Temperature Knob
The center knob changes the temperature of the air
coming through the system. Turn this knob toward red
(clockwise) for warmer air. Turn it toward blue
(counterclockwise) for cooler air.
Mode Knob
The right knob has several settings to control the
direction of airflow:
MAX: This setting recirculates much of the air inside
your vehicle and sends it through the instrument panel
outlets. The air conditioning compressor will run
automatically in this setting unless the outside
temperature is below 40
F (4
C). (Even when the
compressor is running, you can control the temperature.)
NORM: This setting brings in outside air and sends it
through the instrument panel outlets. The air
conditioning compressor will run automatically in this
setting unless the outside temperature is below 40
F
(4
C). (Even when the compressor is running, you can
control the temperature.)

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BI-LEV: This setting brings in outside air and directs it
two ways. Half of the air is directed through the
instrument panel outlets. Most of the remaining air is
directed through the floor ducts and a little to the defrost
and side window vents. The air conditioning compressor
will run automatically in this setting unless the outside
temperature is below 40
F (4
C).
VENT: This setting brings in outside air and directs it
through the instrument panel outlets.
HTR: This setting sends most of the air through the
ducts near the floor. The rest comes out of the defroster
and side window vents.
BLEND: This setting allows half of the air to go to the
floor ducts and half to the defroster and side window
vents. The air conditioning compressor will run
automatically in this setting unless the outside
temperature is below 40
F (4
C).
FRONT: This setting directs most of the air
through the defroster and side window vents. Some of
the air also goes to the floor ducts. The air conditioning
compressor will run automatically in this setting unless
the outside temperature is below 40
F (4
C).Air Conditioning
On very hot days, open the windows long enough to let
hot, inside air escape. This reduces the time for the
vehicle to cool down.
For a quick cool
-down on very hot days, use MAX with
the temperature knob all the way in the blue area. If this
setting is used for long periods of time, the air in your
vehicle may become too dry.
For normal cooling on hot days, use NORM with the
temperature knob in the blue area. The system will bring
in outside air and cool it.
On cool, but sunny days, the sun may warm your upper
body, but your lower body may not be warm enough.
You can use BI
-LEV and set the temperature knob to a
comfortable setting. The system will bring in outside air
and direct it to your upper body, while sending slightly
warmed air to your lower body. You may notice this
temperature difference more at some times than others.

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Driver's Temperature Knob
The center knob sets the temperature for the driver's
outlets. Turn the knob toward red (clockwise) for
warmer air. Turn it toward blue (counterclockwise) for
cooler air.
Passenger's Temperature Lever
The bottom lever adjusts the air temperature on the
passenger's side independent of the temperature set by
the driver. Slide the lever toward the right to raise the
temperature. Slide the lever toward the left to lower
the temperature.
Mode Knob
The right knob has several settings to control the
direction of airflow. To access the various modes
available, turn the mode knob to the desired mode.
MAX: This setting recirculates much of the air inside
your vehicle and sends it through the instrument panel
outlets. The air conditioning compressor will run
automatically in this setting unless the outside
temperature is below 40
F (4
C). (Even when the
compressor is running, you can control the temperature.)NORM: This setting brings in outside air and sends it
through the instrument panel outlets. The air
conditioning compressor will run automatically in this
setting unless the outside temperature is below 40
F
(4
C). (Even when the compressor is running, you can
control the temperature.)
BI
-LEV: This setting brings in outside air and directs it
two ways. Half of the air is directed through the
instrument panel outlets. Most of the remaining air is
directed through the floor ducts and a little to the defrost
and side window vents. The air conditioning compressor
will run automatically in this setting unless the outside
temperature is below 40
F (4
C). (Even when the
compressor is running, you can control the temperature.)
VENT: This setting brings in outside air and directs it
through the instrument panel outlets.
HTR: This setting sends most of the air through the
ducts near the floor. The rest comes out of the defroster
and side window vents.
BLEND: This setting allows half of the air to go to the
floor ducts and half to the defroster and side window
vents. The air conditioning compressor will run
automatically in this setting unless the outside
temperature is below 40
F (4
C). (Even when the
compressor is running, you can control the temperature.)

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FRONT: This setting directs most of the air
through the defroster and side window vents. Some of
the air goes to the floor ducts and the side window vents.
The air conditioning compressor will run automatically
in this setting unless the outside temperature is below
40
F (4
C). (Even when the compressor is running, you
can control the temperature.)
Air Conditioning
On very hot days, open the windows long enough to let
hot, inside air escape. This reduces the time for the
vehicle to cool down.
For a quick cool
-down on very hot days, use MAX with
the temperature knob and lever all the way in the blue
area. If this setting is used for long periods of time, the
air in your vehicle may become too dry.
For normal cooling on hot days, use NORM with the
temperature knob and lever in the blue area. The system
will bring in outside air and cool it.
On cool, but sunny days, the sun may warm your upper
body, but your lower body may not be warm enough.
You can use BI
-LEV and set the temperature knob to a
comfortable setting. The system will bring in outside air
and direct it to your upper body, while sending slightly
warmed air to your lower body. You may notice this
temperature difference more at some times than others.Heating
On cold days, use HTR with the temperature knob and
lever all the way in the red area. The system will bring
in outside air, heat it and send it to the floor ducts.
If your vehicle has an engine coolant heater, you can use
it to help your system provide warm air faster when it's
cold outside
-- 0
F (-18
C) or lower. An engine
coolant heater warms the coolant your engine and
heating system use to provide heat. See ªEngine Coolant
Heaterº in the Index.
Ventilation
For mild outside temperatures, when little heating or
cooling is needed, use VENT to direct outside air through
your vehicle. Your vehicle also has the flow
-through
ventilation system described later in this section.
Defogging and Defrosting
Your system has two settings for clearing the front and side
windows. To defrost the windows quickly, use FRONT with
the temperature knob all the way in the red area.
For maximum defroster performance, set both driver and
passenger temperature controls to the warmest setting.
To warm passengers while keeping the windows clear,
use BLEND.

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3-7 Dual Automatic ComforTemp Climate
Control (If Equipped)
With this system, you set a temperature. You can then
either let the system automatically control airflow
direction and force to maintain the temperature, or you
can manually adjust it. The system works best if you
keep your windows closed while using it.
Automatic Control
For the most efficient operation, you should set the
system temperature and press AUTO. The system will
select the best fan speed and airflow settings to keep you
comfortable. The air conditioning compressor will run if
the outside temperature is above 40
F (4
C). You may
notice a delay of two to three minutes before the fan
comes on at start up in cool weather.Temperature Control
The TEMP switch sets the temperature for the entire system
when the light on the DUAL button isn't lit. If the DUAL
button light is lit, this master temperature control sets the
temperature for the driver only. Press the up arrow to raise the
temperature and press the down arrow to lower the
temperature. The display will show your selection for a few
seconds, then the outside temperature will be displayed. If
you push the AUTO button, the system will control the fan
speed and airflow.
Passenger's Temperature Control
The PASSENGER CONTROL buttons with the arrows
adjust the temperature on the passenger's side so it is
warmer or cooler than the temperature set by the driver.
Push the DUAL button so that the indicator light is lit.
Press the right arrow button to raise the temperature.
Press the left arrow button to lower the temperature. The
display will not show the passenger's temperature, only
that of the driver. Indicators in the passenger control
section will show passenger temperature relative to the
driver's set temperature.

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The amber light indicates the same temperature as
set for the driver.

The red lights indicate a warmer temperature than
that of the driver.

The blue lights indicate a cooler temperature than
that of the driver.
Manual Control
If you prefer to manually control the heating, cooling
and ventilation in your vehicle, you can select airflow
direction, fan speed, outside or recirculated air and air
compressor operation with the following buttons:
AIR FLOW: This control has several settings to control
the direction of airflow when the system is not in AUTO.
To access the various modes available, continue to press
the AIR FLOW rocker button up or down until the
desired mode appears in the display:

WINDSHIELD/FLOOR: This setting directs half
of the air to the floor ducts and half to the defroster
and side window vents.

MID/FLOOR: This setting directs half of the air
through the instrument panel outlets. Most of the
remaining air is directed through the floor ducts and
a little to the defroster and side window vents.
MID: This setting directs air through the instrument
panel outlets.

FLOOR: This setting sends most of the air through
the ducts near the floor. The rest comes out of the
defroster and side window vents.
FRONT: This setting brings in outside air and directs
most of the air through the defrost vent. Some of the air also
goes to the floor ducts and the side window defogger outlets.
The indicator on the button will light and WINDSHIELD
will be lit in the display. The air conditioning compressor will
run automatically in this setting unless the outside
temperature is below 40F (4C).
VENT: This pushbutton turns the air conditioning
compressor on and off. The indicator is lit when the
compressor is turned off. Recirculation is not permitted
when the compressor is off. The system will try to control
the temperature automatically, but without the compressor.
VENT is not permitted in FRONT defrost mode. If the
VENT button is pushed while in FRONT defrost mode,
the indicator will light for one second and then turn off.

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NOTICE:
Do not attach anything like a temporary vehicle
license or decal across the defogger grid.
NOTICE:
Don't use a razor blade or anything else sharp on
the inside of the rear window. If you do, you
could cut or damage the warming grid, and the
repairs wouldn't be covered by your warranty.
Ventilation System
Adjust the direction
of airflow by moving
the vents.
Your vehicle's flow
-through ventilation system supplies
outside air into the vehicle when it is moving. Outside
air will also enter the vehicle when the air conditioning
fan is running.
If the airflow seems very low when the fan is adjusted to
the highest setting regardless of the mode setting, your
passenger compartment air filter may need to be
replaced. See ªMaintenance Scheduleº or ªPassenger
Compartment Air Filterº in the Index.

6-
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Section 6 Service and Appearance Care
Here you will find information about the care of your vehicle. This section begins with service and fuel information,
and then it shows how to check important fluid and lubricant levels. There is also technical information about your
vehicle, and a part devoted to its appearance care.
6
-2 Service
6
-3 Fuel
6
-5 Fuels in Foreign Countries
6
-5 Filling Your Tank
6
-8 Checking Things Under the Hood
6
-11 Engine Oil
6
-16 Engine Air Cleaner/Filter
6
-17 Passenger Compartment Air Filter
6
-18 Automatic Transaxle Fluid
6
-21 Engine Coolant
6
-24 Power Steering Fluid
6
-26 Windshield Washer Fluid
6
-27 Brakes
6
-30 Battery
6
-31 Bulb Replacement
6
-40 Tires6
-50 Appearance Care
6
-50 Cleaning the Inside of Your Vehicle
6
-53 Cleaning Glass Surfaces
6
-53 Cleaning the Outside of the Windshield and
Wiper Blades
6
-53 Cleaning the Outside of Your Vehicle
6
-55 Cleaning Aluminum Wheels (If Equipped)
6
-55 Cleaning Tires
6
-57 GM Vehicle Care/Appearance Materials
6
-58 Vehicle Identification Number (VIN)
6
-58 Electrical System
6
-64 Replacement Bulbs
6
-64 Capacities and Specifications
6
-65 Air Conditioning Refrigerants
6
-65 Normal Maintenance Replacement Parts
6
-65 Vehicle Dimensions