Air Conditioning System (for Manual Air Conditioning System)

AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Manual Air Conditioning System): B1412/12: Ambient Temperature Sensor Circuit
B1412/12 - Ambient Temperature Sensor Circuit

DESCRIPTION

The ambient temperature sensor is installed in front of the condenser.

The air conditioning amplifier applies a voltage (5 V) to the ambient temperature sensor and reads voltage changes as changes in the resistance of the ambient temperature sensor.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM (AMBIENT TEMP SENSOR)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON and turn the Techstream main switch on.

(c) Select the item below in the Data List, and read the value displayed on the Techstream.

Data List / Air Conditioner





OK:

The display is as specified in the normal condition column.

Result:





C -- REPLACE AIR CONDITIONING AMPLIFIER Removal

B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Air Conditioning System (for Manual Air Conditioning System)
A -- Continue to next step.

2. INSPECT COOLER THERMISTOR (AMBIENT TEMPERATURE SENSOR)

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





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

Standard resistance:





NOTICE:
* Touching the sensor even slightly 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 (see the graph).

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

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

(a) Disconnect the A7 sensor connector.





(b) Disconnect the D37 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 Removal