LR3/Disco 3
The evaporator temperature sensor is a NTC thermistor that provides the ATCM with a temperature signal from the
downstream side of the evaporator. The evaporator temperature sensor is installed in the right side of the heater
assembly casing.
The ATCM uses the input from the evaporator temperature sensor to control the load of the A/C compressor and thus the
operating temperature of the evaporator.
IN-VEHICLE TEMPERATURE SENSOR
The in-vehicle temperature sensor is a NTC thermistor installed behind a grill on the driver side of the center console
finisher. The sensor is connected to a tube, the other end of which is connected to a venturi on the side casing of the
heater. An air bleed from the heater, through the venturi, induces a flow of air down the tube, which draws cabin air
through the grill and over the sensor.
HUMIDITY SENSOR (WHERE FITTED)
The humidity sensor is a capacitive device integrated into the in-vehicle temperature sensor (see above).
The humidity sensor element is built out of a film capacitor on different substrates. The dielectric is a polymer which
absorbs or releases water proportional to the relative humidity of the air being drawn through the sensor, and thus
changes the capacitance of the capacitor. For protection, the sensor element is contained in a nylon mesh cover.
The humidity sensor and the in-vehicle temperature sensor are connected to a Printed Circuit Board inside the sensor
housing. The PCB is powered by a 5V feed from the ATCM. Separate signals of temperature and relative humidity are
transmitted from the PCB to the ATCM.
SUNLIGHT SENSOR
