Air Conditioning System (For Automatic Air Conditioning System)

HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System): B1413/13: Evaporator Temperature Sensor Circuit
B1413/13 - Evaporator Temperature Sensor Circuit

DESCRIPTION

The evaporator temperature sensor is installed on the evaporator in the air conditioning unit to detect the cooled air temperature that has passed through the evaporator and to control the air conditioning. It sends appropriate signals to the A/C amplifier. The resistance of the evaporator temperature sensor changes in accordance with the cooled air temperature that has passed through the evaporator. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The A/C amplifier applies voltage (5 V) to the evaporator temperature sensor and reads voltage changes as the resistance of the evaporator temperature sensor changes. This sensor is used for frost prevention.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Body / Air Conditioner / Data List.

(e) Check the value(s) by referring to the table below.

Air Conditioner

Air Conditioner:

OK:

The display is as specified in the Normal Condition column.

Result:





C -- REPLACE A/C AMPLIFIER Removal

B -- PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Air Conditioning System (For Automatic Air Conditioning System)
A -- Continue to next step.

2. INSPECT EVAPORATOR TEMPERATURE SENSOR

(a) Remove the evaporator temperature sensor.

(b) Disconnect the evaporator temperature sensor connector.





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

Standard Resistance:





NOTICE:
- Hold the sensor only by its connector. Touching the sensor may change the resistance value.
- When measuring, the sensor temperature must be the same as the ambient temperature.

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

Text in Illustration

Text in Illustration:

NG -- REPLACE EVAPORATOR TEMPERATURE SENSOR Removal
OK -- Continue to next step.

3. INSPECT AIR CONDITIONING HARNESS (A/C AMPLIFIER - EVAPORATOR TEMPERATURE SENSOR)

(a) Remove the air conditioning harness.





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





Standard Resistance:





Text in Illustration

Text in Illustration:

NG -- REPLACE AIR CONDITIONING HARNESS Disassembly

OK -- REPLACE A/C AMPLIFIER Removal