Passenger's Side Seat Ventilation Level Does Not Change (Display Changes, But Operation Does Not Change)

Trouble symptom: 

When the passenger's side seat ventilation switch is touched, the display on the center information display changes, but the operation mode does not change.

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 SEAT VENTILATION SWITCH DISPLAY  .
   1. Turn the ignition switch to ON.
   2. Touch the seat indicator on the center information display.
   3. Check if the seat ventilation switch is displayed under the seat heater switch.

      Is the seat ventilation switch displayed?

      Yes:  Go to  2 .

      No:  Ref. to VENTILATION SEAT (DIAGNOSTICS)>DIAGNOSTICS WITH PHENOMENON>INSPECTION>SEAT VENTILATION SWITCH IS NOT DISPLAYED .

2. CHECK IF BOTH THE BACKREST SIDE AND CUSHION SIDE ARE OPERATING  .
   1. Start the engine.
   2. Turn the seat ventilation ON.
   3. Check if the blowers for both the backrest and cushion are operating.

      Are both the backrest side and cushion side not functioning properly?

      Yes:  Go to  3 .

      No:  Ref. to VENTILATION SEAT (DIAGNOSTICS)>DIAGNOSTICS WITH PHENOMENON>INSPECTION>BLOWER ON ONE SIDE (BACKREST SIDE OR CUSHION SIDE) DOES NOT OPERATE .

3. CHECK DTC  .
   1. Turn the ignition switch to ON.
   2. Read the following DTCs using Subaru Select Monitor. Ref. to Ventilation Seat (Diagnostics)>Diagnostic Trouble Code (DTC) . Ref. to BODY CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) . Ref. to AIR CONDITIONER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) . Ref. to COCKPIT CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .
      • Ventilation Seat
      • Body Control
      • Air Conditioner
      • Cockpit Control

      Are any DTCs displayed?

      Yes:  Perform the diagnosis for the displayed DTCs. Ref. to Ventilation Seat (Diagnostics)>Diagnostic Trouble Code (DTC) . Ref. to BODY CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) . Ref. to AIR CONDITIONER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) . Ref. to COCKPIT CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

      No:  Go to  4 .

4. CHECK CONNECTOR  .
   1. Turn the ignition switch to OFF.
   2. Check malfunctions (terminal bends, connecting condition, etc.) of the seat ventilation control module connector (St41), seat connectors (L57) (R57), coupling connectors (B43) (L51) (R51) (St21) (St22), and blower connectors (St71) (St72).

      Is the check result OK?

      Yes:  Go to  5 .

      No:  Repair the connector.

5. CHECK HARNESS (OPEN CIRCUIT)  .
   1. Disconnect the passenger's side ventilation blower connector (St71), seat connector (St1), and in-seat connector (St21).
   2. Using the tester, measure the resistance between terminals.

      Connector and terminal 

      (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:

      Is the resistance less than 5 Ω?

      Yes:  Replace the power unit blower cushion RH and the power unit blower backrest RH. Ref. to SEATS>SEAT VENTILATION SYSTEM .

      No:  Repair or replace the open circuit of harness.