Illumination Of Rear Seat Heater Does Not Illuminate

Wiring diagram: 

Clearance and illumination light system Ref. to WIRING SYSTEM>CLEARANCE LIGHT AND ILLUMINATION LIGHT SYSTEM>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK ADAPTER HARNESS  .
   1. Turn the ignition switch to OFF.
   2. Remove the seat heater switch. Ref. to SEATS>SEAT HEATER>INSTALLATION>REAR SEAT HEATER SWITCH 
   3. Check the continuity between the adapter harness connectors.

      Connector & terminal 

      LH side 

      (C3) No. 7 - (C34) No. 6:

      (C3) No. 8 - (C34) No. 7:

      RH side 

      (C3) No. 7 - (C33) No. 4:

      (C3) No. 8 - (C33) No. 5:

   Is there continuity between the terminals?

   Yes  : Go to  2.

   No  : Replace the adapter harness.

2. CHECK SEAT HEATER SWITCH UNIT  .

   Apply battery voltage between seat heater switch terminals, and perform the inspection. Ref. to SEATS>SEAT HEATER>INSPECTION>SEAT HEATER SWITCH 

   Do the illuminations come on?

   Yes  : Go to  3.

   No  : Replace the seat heater switch. Ref. to SEATS>SEAT HEATER>REMOVAL>REAR SEAT HEATER SWITCH 

3. CHECK POWER SUPPLY CIRCUIT  .
   1. Turn the ignition switch to ON.
   2. Turn the lighting switch to the switch 2 (HEAD) position.
   3. Measure the voltage between connector terminal and chassis ground.

      Connector & terminal 

      (R58) No. 7 (+) - Chassis ground (-):

   Is the voltage 10 V or more?

   Yes  : Go to  8.

   No  : Go to  4.

4. CHECK HARNESS  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector of body integrated unit.
   3. Measure the resistance between terminals of the seat heater switch and the body integrated unit.

      Connector & terminal 

      (R58) No. 7 - (B71) No. 11:

   Is the resistance less than 10 Ω?

   Yes  : Go to  5.

   No  : Repair or replace the defective part.

5. CHECK INPUT OF BODY INTEGRATED UNIT  .
   1. Turn the ignition switch to ON.
   2. Using Subaru Select Monitor, display [Lighting I Switch Input] in [Data Monitor] of [Body Control]. Ref. to COMMON (DIAGNOSTICS)>DATA MONITOR>OPERATION
   3. Set the lighting switch to the I position and release your hand.

   Does the indication change between [OFF] ←→ [ON] according to the switch operation?

   Yes  : Replace the body integrated unit. Ref. to BODY CONTROL/COMMUNICATION SYSTEM>BODY INTEGRATED UNIT

   No  : Go to  6.

6. CHECK LIGHTING SWITCH  .
   1. Turn the ignition switch to OFF.
   2. Check the lighting switch. Ref. to LIGHTING SYSTEM>COMBINATION SWITCH (LIGHT)>INSPECTION>LIGHTING SWITCH

   Is the lighting switch OK?

   Yes  : Go to  7.

   No  : Replace the lighting switch. Ref. to LIGHTING SYSTEM>COMBINATION SWITCH (LIGHT)

7. CHECK HARNESS  .
   1. Disconnect the connectors of body integrated unit and combination switch (light).
   2. Measure the resistance between terminals of the body integrated unit and the combination switch (light).

      Connector & terminal 

      Other than for C0 

      (i83) No. 20 - (i131) No. 19:

      (i83) No. 35 - (i131) No. 18:

      For C0 

      (i83) No. 20 - (i131) No. 18:

      (i83) No. 35 - (i131) No. 19:

   Is the resistance less than 10 Ω?

   Yes  : Replace the body integrated unit. Ref. to BODY CONTROL/COMMUNICATION SYSTEM>BODY INTEGRATED UNIT

   No  : Repair or replace the defective part.

8. CHECK HARNESS  .
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector of combination meter.
   3. Measure the resistance between terminals of the seat heater switch and the combination meter.

      Connector & terminal 

      (R58) No. 8 - (i97) No. 34:

   Is the resistance less than 10 Ω?

   Yes  : Go to  9.

   No  : Repair or replace the defective part.

9. CHECK HARNESS  .

   Measure the resistance between the combination meter and the chassis ground.

   Connector & terminal 

   (i97) No. 40 - Chassis ground:

   Is the resistance less than 10 Ω?

   Yes  : Replace the combination meter. Ref. to INSTRUMENTATION/DRIVER INFO>COMBINATION METER

   No  : Repair or replace the defective part.