DTC B14D4: Air Mix Door Actuator Circuit Open (Rear HVAC)

DTC detecting condition: 

Rear air mix door actuator circuit is open.

Trouble symptom: 

Temperature cannot be adjusted.

Wiring diagram: 

Air conditioning system Ref. to WIRING SYSTEM>Air Conditioning System>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK CONNECTOR  .
   1. Check connecting condition of the A/C control module connector and rear air mix door actuator connector.
   2. Read the DTC of [Air Conditioner] using the Subaru Select Monitor. Ref. to AIR CONDITIONER (DIAGNOSTICS)>Diagnostic Trouble Code (DTC) .

   Is DTC B14D4 displayed? (Current malfunction)

   Yes  : Go to  2.

   No:  Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

   NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
2. CHECK ACTUATOR  .
   1. Disconnect the rear air mix door actuator.
   2. Short No. 2 and No. 1 in (AD47) connector.
   3. Read the DTC of [Air Conditioner] using the Subaru Select Monitor. Ref. to AIR CONDITIONER (DIAGNOSTICS)>Diagnostic Trouble Code (DTC) .

   Is DTC B14D5 displayed? (Current malfunction)

   Yes:  Replace the rear air mix door actuator. Ref. to AIR CONDITIONER>AIR MIX DOOR ACTUATOR .

   No:  Go to  3.

3. CHECK HARNESS  .
   1. Restore the temporary shorted lines made in step 2.
   2. Turn the ignition switch to ON.
   3. Using a tester, measure the voltage between rear air mix door actuator terminals.

      Connector & terminal 

      (AD47) No. 3 (+) - (AD47) No. 1 (-):

      Is the voltage 4.5 - 5.5 V? 

      Yes  : Go to  4.

      No:  Repair or replace the open circuit of harness.

   4. CHECK HARNESS (OPEN CIRCUIT)  .
      1. Disconnect the connector from A/C control module.
      2. Using a tester, check the continuity between A/C control module connector and rear air mix door actuator terminals.

         Connector & terminal 

         (i329) No. 12 - (AD47) No. 3:

         (i329) No. 24 - (AD47) No. 1:

         (i80) No. 26 - (AD47) No. 2:

   Is there continuity?

   Yes:  Replace the A/C control module. Ref. to AIR CONDITIONER>CONTROL UNIT .

   No:  Repair or replace the open circuit of harness.