Cabin Temperature Sensor / Switch: Testing and Inspection

IN-VEHICLE SENSOR





Component Description

In-vehicle sensor





The in-vehicle sensor (1) is located on instrument lower panel LH. It converts variations in temperature of compartment air drawn from the aspirator into a resistance value. It is then input into the front air control.

Aspirator





The aspirator (1) is located on LH side of heater and cooling unit. It produces vacuum pressure due to air discharged from the heater and cooling unit, continuously taking compartment air in the aspirator.









Diagnosis Procedure
Regarding Wiring Diagram information, Air Conditioner Control Coupe Automatic Air Conditioner or Air Conditioner Control Sedan Automatic Air Conditioner.

DIAGNOSTIC PROCEDURE





SYMPTOM: In-vehicle sensor circuit is open or shorted.
1.CHECK VOLTAGE BETWEEN IN-VEHICLE SENSOR HARNESS CONNECTOR AND BODY GROUND
1. Disconnect in-vehicle sensor connector M34.
2. Press ignition switch ON.





3. Check voltage between in-vehicle sensor harness connector
M34 terminal 1 and ground.





Is the inspection result normal?
YES - GO TO 2
NO - GO TO 4
2.CHECK IN-VEHICLE SENSOR GROUND CIRCUIT BETWEEN IN-VEHICLE SENSOR AND FRONT AIR
CONTROL





1. Press ignition switch OFF.
2. Disconnect front air control connector M152.
3. Check continuity between front air control harness connector
M152 (A) terminal 26 and in-vehicle sensor harness connector
M34 (B) terminal 2.





If OK, check harness for short.
Is the inspection result normal?
YES - GO TO 3
NO - Repair harness or connector.
3.CHECK IN-VEHICLE SENSOR
Check in-vehicle sensor. In-Vehicle Sensor.
Is the inspection result normal?
YES - 1. Replace front air control. Service and Repair.
2. Confirm system operation.
NO - 1. Replace in-vehicle sensor. In-Vehicle Sensor.
2. Confirm system operation.
4.CHECK IN-VEHICLE SENSOR CIRCUIT BETWEEN AMBIENT SENSOR AND FRONT AIR CONTROL





1. Press ignition switch OFF.
2. Disconnect front air control connector M152.
3. Check continuity between front air control harness connector
M152 (A) terminal 27 and in-vehicle sensor harness connector
M34 (B) terminal 1.





If OK, check harness for short.
Is the inspection result normal?
YES - 1. Replace front air control. Service and Repair.
2. Confirm system operation.
NO - Repair harness or connector.




Component Inspection

In-vehicle Sensor





After disconnecting in-vehicle sensor connector M34, measure resistance between terminals 1 and 2 at sensor side, using the table below.





If NG, replace in-vehicle sensor. In-Vehicle Sensor.