Humidity Sensor: Testing and Inspection

HEATING / AIR CONDITIONING: HUMIDITY SENSOR: INSPECTION

1. INSPECT AIR CONDITIONING THERMISTOR ASSY ASSEMBLY

(a) for Glass temperature sensor

(1) Remove the air conditioning thermistor assembly (glass temperature sensor).





(2) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NOTICE:
* Hold the sensor only by its connector. Touching the sensor may change the resistance value.
* When measuring, the sensor temperature must be the same as the ambient temperature.

HINT
As the temperature increases, the resistance decreases (see the graph).

If the resistance is not as specified, replace the air conditioning thermistor assembly (glass temperature sensor).

Text in Illustration





(b) for Glass surroundings temperature sensor

(1) Remove the air conditioning thermistor assembly (glass surroundings temperature sensor).





(2) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NOTICE:
* Hold the sensor only by its connector. Touching the sensor may change the resistance value.
* When measuring, the sensor temperature must be the same as the ambient temperature.

HINT
As the temperature increases, the resistance decreases (see the graph).

If the resistance is not as specified, replace the air conditioning thermistor assembly (glass surroundings temperature sensor).

Text in Illustration





(c) for Glass humidity sensor

(1) Remove the air conditioning thermistor assembly (glass humidity sensor) with the connector still connected.





(2) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





NOTICE:
* Do not touch the sensor as body heat will affect the inspection results. When performing the inspection, hold the sensor by its connector.
* Allow the sensor to acclimate to the ambient temperature and humidity before performing the inspection.
* The specified voltages in the table above are based on inspections performed when the ambient temperature is 25°C (77°F).

HINT
As the humidity increases, the voltage increases (see the graph).

If the voltage is not as specified, replace the air conditioning thermistor assembly (glass humidity sensor).

Text in Illustration