Room Temperature Sensor Circuit - Air Conditioning System

AIR CONDITIONING: AIR CONDITIONING SYSTEM: 11: Room Temperature Sensor Circuit

DTC 11 - Room Temperature Sensor Circuit

DESCRIPTION

This sensor detects the temperature inside the cabin and sends appropriate signals to the A/C amplifier.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. INSPECT AIR CONDITIONING AMPLIFIER (TR, SG)




(a) Remove the A/C amplifier with the connectors still connected.
(b) Turn the ignition switch ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:





HINT: As the temperature increases, the voltage decreases.

OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

NG -- Continue to next step.

2. INSPECT COOLER THERMISTOR (ROOM TEMPERATURE SENSOR)




(a) Remove the cooler thermistor (room temp. sensor).




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





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

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

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

3. CHECK HARNESS AND CONNECTOR (COOLER THERMISTOR (ROOM TEMPERATURE SENSOR) - A/C AMPLIFIER)
(a) Check for open and short circuit in the harness and the connector between the cooler thermistor (room temp. sensor) and the A/C amplifier Electronic Circuit Inspection Procedure.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. CHECK DTC
(a) Start up the DTC check mode.
(b) Check that DTC 11 is not output again.
Result:





B -- SYSTEM IS OK
A -- REPLACE AIR CONDITIONING AMPLIFIER