Room Temperature Sensor Circuit - Air Conditioning System (for Automatic Air Conditioning System)

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System): B1411/11: Room Temperature Sensor Circuit
B1411/11 - Room Temperature Sensor Circuit

DESCRIPTION

The cooler thermistor (room temperature sensor) for the front seat is installed in the instrument panel to detect the room temperature and control the heater and air conditioner auto mode. The resistance of the room temperature sensor changes in accordance with the front room temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The air conditioning amplifier assembly applies voltage (5 V) to the room temperature sensor and reads voltage changes as the resistance of the room temperature sensor changes. This sensor also sends the appropriate signals to the air conditioning amplifier assembly.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM (ROOM TEMPERATURE SENSOR)

(a) Use the Data List to check if the cooler thermistor (room temperature sensor) is functioning properly Air Conditioning System (for Automatic Air Conditioning System).

Air Conditioner





OK:

The display is as specified in the normal condition column.

Result





C -- INSPECT COOLER THERMISTOR (ROOM TEMPERATURE SENSOR)

B -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Removal

A -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Air Conditioning System (For Automatic Air Conditioning System)

2. INSPECT COOLER THERMISTOR (ROOM TEMPERATURE SENSOR)

(a) Remove the cooler thermistor (room temperature sensor) Removal.





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

Standard Resistance:





Text in Illustration





NOTICE:
* Even slightly touching the sensor may change the resistance value. Be sure to hold the connector of the sensor.
* When measuring, the sensor temperature must be the same as the ambient temperature.

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

NG -- REPLACE COOLER THERMISTOR (ROOM TEMPERATURE SENSOR) Removal
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (ROOM TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER)

(a) Disconnect the F26 sensor connector.

(b) Disconnect the F42 amplifier 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