Blower On One Side (Backrest Side Or Cushion Side) Does Not Operate

Trouble symptom: 

• When the seat ventilation is activated, the blower on the backrest side operates, but the one on the cushion side does not operate.
• When the seat ventilation is activated, the blower on the cushion side operates, but the one on the backrest side does not operate.

Trouble causes: 

• Seat ventilation control module failure
• A/C control module failure
• Seat ventilation circuit failure
• Seat heater circuit failure
• Center information display failure
• Cockpit control module failure
• Seat ventilation blower failure

Wiring diagram: 

Seat ventilation system Ref. to WIRING SYSTEM>SEAT VENTILATION SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK CONNECTOR  .
   1. Turn the ignition switch to OFF.
   2. Check connecting condition of the seat ventilation control module connector (St41), seat connectors (L57) (R57), coupling connectors (B43) (L51) (R51) (St21) (St22), and blower connectors (St71) (St72) (St73) (St74).
      NOTE: Perform the check only for the connectors related to the parts not functioning properly.

      Is the check result OK?

      Yes:  Go to  2 .

      No:  Repair the connector.

2. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Disconnect the seat connectors (St1) (St2), in-seat connectors (St3) (St4) (St21) (St22), and blower connectors (St71) (St72) (St73) (St74).
   2. Using the tester, measure the resistance between terminals.
      NOTE: Perform the check only for the harnesses related to the parts not functioning properly.

      Connector and terminal 

      Driver's side 

      (St72) No. 1 - (St2) No. 13:

      (St72) No. 2 - (St2) No. 11:

      (St72) No. 3 - (St2) No. 8:

      (St4) No. 7 - (St2) No. 8:

      (St4) No. 12 - (St2) No. 13:

      (St4) No. 14 - (St2) No. 11:

      (St22) No. 7 - (St74) No. 3:

      (St22) No. 12 - (St74) No. 1:

      (St22) No. 14 - (St74) No. 2:

      Passenger's side 

      (St71) No. 1 - (St1) No. 13:

      (St71) No. 2 - (St1) No. 11:

      (St71) No. 3 - (St1) No. 8:

      (St3) No. 4 - (St1) No. 11:

      (St3) No. 5 - (St1) No. 13:

      (St3) No. 6 - (St1) No. 8:

      (St21) No. 4 - (St73) No. 2:

      (St21) No. 5 - (St73) No. 1:

      (St21) No. 6 - (St73) No. 3:

      Is the resistance less than 5 Ω?

      Yes:  Replace the power unit blower cushion or the power unit blower backrest that is not functioning properly. Ref. to SEATS>SEAT VENTILATION SYSTEM .

      No:  Repair or replace the open circuit of harness.