Ambient temperature sensor circuit

The ambient temperature sensor is installed in the front part of the condenser to detect the ambient temperature and control the air conditioner. The sensor is connected to the combination meter and detects fluctuations in the ambient temperature. This data is used for controlling the room temperature.

The sensor sends a signal to the air conditioning amplifier via the combination meter. The resistance of the ambient temperature sensor changes in accordance with the ambient temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

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. The combination meter sends the read signal to the air conditioning amplifier via can communication.

1. 1
   Read value of intelligent tester (ambi temp sens)
2. 2
   Connect the intelligent tester (with can vim) to the dlc3.
3. 3
   Turn the ignition switch on and turn the intelligent tester main switch on.
4. 4
   Select the item below in the data list, and read the value displayed on the intelligent tester.

   

2. Inspect ambient temperature sensor

1. 1
   Remove the ambient temperature sensor.
2. 2
   Measure the resistance of the sensor.

Standard resistance

• 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.

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

3. Check wire harness (ambient temperature sensor - combination meter)

1. 1
   Disconnect the a17 sensor connector.
2. 2
   Disconnect the e19 meter connector.
3. 3
   Measure the resistance of the wire harness side connectors.

Standard resistance