Cold Air Does Not Come Out Even When The A/C Switch Is Pressed. The Glass Cannot Be Defogged. (Compressor Does Not Operate.)

Trouble symptom: 

Compressor does not operate after turning the A/C switch to ON and fan dial between LO and HI.

Trouble causes: 

Compressor failure

Wiring diagram: 

Air conditioning system Refer to WIRING SYSTEM>AIR CONDITIONING SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK A/C CONTROL PANEL. 
   1. Leave the vehicle under the condition at ambient temperature of 15°C (59°F) or more. 
   2. Turn the ignition switch to ON. 
   3. Turn the fan dial to the maximum position. 
   4. Press the A/C switch. 

      Is "A/C" displayed on the A/C control panel?

      Yes:  Go to  1.

      No:  Replace the A/C control panel. Refer to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>CONTROL PANEL>REMOVAL .

2. CHECK EVAPORATOR SENSOR. 

   Using the Subaru Select Monitor, check "Evaporator Temperature" of the current data from the A/C diagnosis. Refer to HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)>READ CURRENT DATA .

   Does the data indicate -0.5°C or more?

   Yes:  Go to  1.

   No:  Go to  1.

3. CHECK EVAPORATOR SENSOR. 

   Check the evaporator sensor. Refer to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>EVAPORATOR SENSOR>INSPECTION .

   Is the check result OK?

   Yes:  Go to  1.

   No:  Replace the evaporator sensor. Refer to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>EVAPORATOR SENSOR>REMOVAL .

4. CHECK PRESSURE SWITCH. 

   Check the pressure switch connection.

   Is the check result OK?

   Yes:  Go to  5.

   No:  Repair the connector.

5. CHECK PRESSURE SWITCH. 

   Using the Subaru Select Monitor, check "A/C Pressure Switch" of the current data from Air Conditioning Diagnosis. Refer to HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)>READ CURRENT DATA .

   Does the data indicate normal?

   Yes:  Go to  10.

   No:  Go to  6.

6. CHECK AMOUNT OF REFRIGERANT PRESSURE. 

   Check the refrigerant pressure. Refer to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET>PROCEDURE>CHECK REFRIGERANT GAS PRESSURE .

   Is the check result OK?

   Yes:  Go to  7.

   No:  Perform repair according to refrigerant pressure inspection.

7. CHECK CONNECTOR. 

   Check poor contact of A/C control panel connector.

   Is the check result OK?

   Yes:  Go to  8.

   No:  Repair the connector.

8. CHECK FUSE. 
   1. Turn the ignition switch to ON. 
   2. Remove a fuse in the fuse & relay box. 
   3. Check the fuse. 

   Is the check result OK?

   Yes:  Go to  9.

   No:  Replace the fuse. If the replaced fuse blows out easily, repair the ground short circuit in harness between the pressure switch and fuse.

9. CHECK PRESSURE SWITCH SIGNAL. 
   1. Turn the ignition switch to OFF. 
   2. Disconnect the A/C control panel connector. 
   3. Turn the ignition switch to ON. 
   4. Measure the voltage between A/C control panel connector terminal and chassis ground. 

   Connector & terminal 

   (i88) No. 11 (+) - Chassis ground (-):

   Is the voltage 10 V or more?

   Yes:  Replace the A/C control panel. Refer to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>CONTROL PANEL>REMOVAL .

   No 

   • Check for open or short circuit in the harness between fuse and A/C control panel.
   • Check for poor contact of pressure switch connector.
10. CHECK CAN COMMUNICATION CIRCUIT. 

    Using the Subaru Select Monitor, check "A/C Switch" of the current data from Engine Diagnosis. Refer to HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)>READ CURRENT DATA .

    Does the data indicate ON?

    Yes:  Go to  12.

    No:  Go to  11.

11. CHECK CAN COMMUNICATION CIRCUIT. 

    Perform the diagnosis for LAN system. Refer to LAN SYSTEM (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

    Is the check result of the LAN system OK?

    Yes:  Replace the A/C control panel. Refer to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>CONTROL PANEL>REMOVAL .

    No:  Repair it according to DTC of LAN system.

12. CHECK A/C RELAY ON SIGNAL. 
    1. Turn the ignition switch to ON. 
    2. Measure the voltage between ECM connector terminal and chassis ground. 

    Connector & terminal 

    Engine type: FA 

    (B134) No. 1 (+) - Chassis ground (-):

    Engine type: EJ 

    (B135) No. 35 (+) - Chassis ground (-):

    Is the voltage 10 V or more?

    Yes:  Go to  13.

    No 

    • Check for open or short in the harness between pressure switch and ECM.
    • Check poor contact of A/C relay connector.
    • Check the A/C relay. Refer to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>RELAY AND FUSE>INSPECTION .
13. CHECK A/C RELAY ON SIGNAL. 
    1. Start the engine. 
    2. Turn the A/C switch to ON. 
    3. Set the temperature control dial to MAX COOL. 
    4. Measure the voltage between ECM connector terminal and chassis ground. 

    Connector & terminal 

    Engine type: FA 

    (B134) No. 1 (+) - Chassis ground (-):

    Engine type: EJ 

    (B135) No. 35 (+) - Chassis ground (-):

    Is the voltage 0 V?

    Yes:  Go to  14.

    No:  Replace the ECM.

14. CHECK MAGNET CLUTCH POWER SUPPLY CIRCUIT. 
    1. Stop the engine. 
    2. Disconnect the magnet clutch connector. 
    3. Start the engine. 
    4. Turn the A/C switch to ON. 
    5. Set the temperature control dial to MAX COOL. 
    6. Measure the voltage between magnet clutch connector terminal and chassis ground. 

    Connector & terminal 

    (F24) No. 1 (+) - Chassis ground (-):

    Is the voltage 10 V or more?

    Yes:  Check the magnet clutch. Refer to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>COMPRESSOR>INSPECTION .

    No 

    • Check for open or short circuit in the harness between fuse and magnet clutch.
    • Check poor contact of A/C relay connector.
    • Check the A/C relay. Refer to HVAC SYSTEM (HEATER, VENTILATOR AND A/C)>RELAY AND FUSE>INSPECTION .