Side Window Demisters; Sun Sensor; System Airflow; Diagnosis And Testing A/C Performance Test - Chrysler 2000 LHS Owner's Manual

24 - 6 HEATING AND AIR CONDITIONING
DESCRIPTION AND OPERATION (Continued)

SIDE WINDOW DEMISTERS

DESCRIPTION
The side window demisters direct air from the
heater assembly through the outlets located on the
top corners of the instrument panel, to the side win-
dows.
OPERATION
Side window demisting is performed when the
mode selector is on FLOOR, DEFROST, MIX OR BI-
LEVEL setting.

SUN SENSOR

DESCRIPTION
The sun sensor is only used on vehicles equipped
with Automatic Temperature Control (ATC). The sen-
sor is mounted on the top of the instrument panel
below the instrument panel top cover (Fig. 3).
OPERATION
The sun sensor is not a thermistor type sensor but
rather a photo diode. For this reason the sun sensor
responds to sun light intensity rather than tempera-
ture. It is used to aid in determining proper mode
door position, temperature door position and blower
speed. The sun sensor is also used to sense day/night
conditions for automatic headlight control if so
equipped, and has an LED indicator for the vehicle
security system.
The sun sensor is not serviceable and must be
replaced if found to be defective.
Fig. 3 Sun Sensor

SYSTEM AIRFLOW

DESCRIPTION
The system draws outside air through the cowl
opening at the base of the windshield. Then it goes
into the plenum chamber above the Heater A/C unit
housing and passes through the evaporator. At this
point airflow can be directed either through or
around the heater core.
OPERATION
Airflow can be adjusted by the blend-air door with
the TEMP control on the control head. After the air
passes the blend air door, the air flow is then
directed from the PANEL, BI-LEVEL (panel and
floor), and FLOOR-DEFROST outlets. Air flow veloc-
ity can be adjusted with the blower speed selector
switch on the control head.
Ambient air intake can be shut off by closing the
recirculating air door. This will recirculate the air
that is already inside the vehicle. See owners manual
for recirculation operation.
DIAGNOSIS AND TESTING
A/C PERFORMANCE TEST
The air conditioning system is designed to remove
heat and humidity from the air entering the passen-
ger compartment. The evaporator, located in the
heater A/C unit, is cooled to temperatures near the
freezing point. As warm damp air passes over the
fins in the evaporator, moisture in the air condenses
to water, dehumidifying the air. High humidity
reduces the evaporator's ability to cool the air. Dur-
ing periods of high heat and humidity, an air condi-
tioning system will be less effective. With the control
module set to RECIRC, only air from the passenger
compartment passes through the evaporator. As the
passenger compartment air dehumidifies, A/C perfor-
mance levels rise.
PERFORMANCE TEST PROCEDURE
Review Safety Precautions and Warnings in this
group before proceeding with this procedure. Air tem-
perature in test room and in vehicle must be 21° C
(70°F) minimum for this test.
NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.
(1) Connect a tachometer and manifold gauge set.
(2) Set controls:
MANUAL A/C
• A/C ON
• Panel Recirculation
• Temperature to full cold
• High blower
LH