B1462

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1462/62: Room Humidity Sensor Circuit
B1462/62 - Room Humidity Sensor Circuit

DESCRIPTION

The air conditioning thermistor assembly (humidity sensor) detects cabin humidity. The voltage of the air conditioning thermistor assembly (humidity sensor) changes in accordance with cabin humidity. The air conditioning amplifier assembly reads changes in the air conditioning thermistor assembly (humidity sensor).

The humidity sensor is integrated with the air conditioning thermistor assembly.





HINT
The whole air conditioning thermistor assembly should be replaced if the humidity sensor is malfunctioning.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Data List.

(e) Check the value(s) by referring to the table below.

Air Conditioner





OK:

The display is as specified in the Normal Condition column.

Result:





B -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Symptom Related Diagnostic Procedures

C -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Removal
A -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)

(a) Disconnect the S3 air conditioning thermistor assembly (humidity sensor) connector.





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

Standard Voltage:





Text in Illustration





NG -- CHECK HARNESS AND CONNECTOR (AIR CONDITIONING THERMISTOR ASSEMBLY (HUMIDITY SENSOR) - AIR CONDITIONING AMPLIFIER ASSEMBLY)
OK -- Continue to next step.

3. INSPECT AIR CONDITIONING THERMISTOR ASSEMBLY (HUMIDITY SENSOR)

(a) Reconnect the S3 air conditioning thermistor assembly (humidity sensor) connector.





(b) Turn the power switch on (IG).

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

Standard Voltage:





NOTICE:
* Do not touch the room humidity sensor because it may be affected by body temperature and may not work properly.
* Hold the sensor only by its connector.
* The output voltage at an ambient temperature of 25°C (77°F) is shown above.

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

Text in Illustration





NG -- REPLACE AIR CONDITIONING THERMISTOR ASSEMBLY (HUMIDITY SENSOR) Removal
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (AIR CONDITIONING THERMISTOR ASSEMBLY (HUMIDITY SENSOR) - AIR CONDITIONING AMPLIFIER ASSEMBLY)

(a) Disconnect the I77 air conditioning amplifier assembly connector.

(b) Disconnect the S3 air conditioning thermistor assembly (humidity sensor) connector.

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

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Removal