rator temperature and prevent evaporator freezing,
an evaporator temperature sensor is used to supply
an evaporator temperature message to the A/C-
heater control. In turn, the powertrain control mod-
ule (PCM) cycles the A/C compressor clutch off and
on as necessary to protect the A/C system from evap-
orator freezing and optimize A/C system perfor-
mance.
AUTOMATIC TEMPERATURE CONTROL (ATC) -
DUAL ZONE
The dual zone automatic temperature control
(ATC) system automatically maintains the interior
comfort level desired by the driver and front seat
passenger. This is accomplished by using two infra-
red sensors within the A/C-heater control which is
located at the center of the instrument panel. The
two infrared sensors independently measure the sur-
face temperature of the driver and front seat passen-
ger.
Based
on
the
sensor
input,
the
system
automatically adjusts the air temperature, the air-
flow volume, the airflow distribution, and amount of
inside air recirculation to maintain front seat occu-
pant comfort, even under changing outside weather
conditions.
When DUAL is displayed on the A/C-heater con-
trol, the driver and passenger air outlet tempera-
tures can be individually adjusted from the two
independent TEMP buttons. When a front seat pas-
senger is not present, pressing the DUAL button will:
• disable the passenger side infrared sensor and
control the entire system based only on the driver
side temperature setting.
• replace the passenger side temperature setting
in the display to the outside temperature reading.
Pressing the DUAL button a second time or adjust-
ing the passenger side TEMP button will:
• reactivate the passenger side infrared sensor.
• return the system to dual independent tempera-
ture operation.
This ATC system offers several manual override
features. The indicator light in both the AUTO HI or
AUTO LO buttons will turn off when the system is
being used in the manual mode. The fan speed, air-
flow distribution, and outside air/recirculated air can
be manually adjusted.
The front blower fan control can be set to any fixed
blower fan speed by pressing the rocker switch up or
down. This allows the front occupants to control the
volume of air circulated in the vehicle and cancel the
auto mode. The fan will now operate at a fixed speed
until additional speeds are selected or until either
the AUTO HI or AUTO LO buttons are pressed. The
system will continue to automatically adjust air tem-
perature and airflow distribution.
When the outside air contains smoke, odors, high
humidity, or if rapid cooling is desired, interior air
can be recirculated by pressing the recirculation but-
ton. The recirculate symbol will illuminate in the dis-
play when this button is selected.
The outside temperature can be shown in the A/C-
heater control display by pressing the OUTSIDE
TEMP button. After pressing this button, the front
seat passenger side temperature setting display will
be replaced with the current outside temperature.
Pressing the OUTSIDE TEMP button again or press-
ing the passenger side TEMP button will return the
display to the passenger side temperature setting.
• The system automatically adjusts the tempera-
ture, mode and fan speed.
• When the heating- A/C system is off, the recir-
culation door is automatically closed to prevent out-
side air from entering the passenger compartment.
• Air conditioning is available in any mode by
pressing the snowflake, A/C on/off, button.
To provide maximum comfort in the automatic
mode during cold start-ups, the blower fan will
remain off and DELAY will appear in the display
until the engine warms up. The estimated the time
remaining until the DELAY is complete will appear
periodically in the display. However, the fan will
engage immediately if the defrost mode is selected or
by pushing the blower switch and manually adjust-
ing the fan speed.
MANUAL TEMPERATURE CONTROL (MTC) -
DUAL ZONE
• The two slide controls enable continuously vari-
able proportioning of the conditioned air.
• The mode control knob enables continuously
variable proportioning of air flow between modes and
has detents adjacent to each icon.
• The blower control provides four separate speeds
and an Off position.
• When the heater-A/C system is off, the HVAC
computer closes the recirculation door to prevent out-
side air from entering the passenger compartment.
• Interior air may be recirculated to speed up
heating or cooling in all modes except defrost and
mix by pressing the Recirculate button on the A/C-
heater control.
• To reduce humidity for rapid defogging, the A/C
compressor runs automatically in modes from “mix”
to full defrost when outside temperatures are above
freezing.
• Air conditioning is available in any mode by
pressing the snowflake, A/C on/off button.
CS
HEATING & AIR CONDITIONING
24 - 5
HEATING & AIR CONDITIONING (Continued)