The Steering Heater Does Not Operate

Wiring diagram: 

Steering heater system Ref. to WIRING SYSTEM>STEERING HEATER SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK POWER SUPPLY INPUT  .
   1. Disconnect the ground terminal from battery sensor and wait for 60 seconds or more. Ref. to REPAIR CONTENTS>NOTE>BATTERY .
   2. Disconnect the steering roll connector and steering heater Control Module connector.
   3. Connect the ground terminal to the battery sensor and turn the ignition switch to ON.
   4. Measure the steering roll connector voltage.

      Connector & terminal 

      (ST12) No. 4 (+) - No. 3 (-)

   Is the voltage 10 - 14 V?

   Yes:  Go to  2.

   No:  Go to  8.

2. CHECK STEERING HEATER SWITCH  .

   Check the steering heater switch. Ref. to POWER ASSISTED SYSTEM (POWER STEERING)>STEERING WHEEL>INSPECTION>STEERING HEATER SWITCH .

   Is the steering heater switch OK?

   Yes:  Go to  3.

   No:  Replace the steering heater switch. Ref. to POWER ASSISTED SYSTEM (POWER STEERING)>STEERING WHEEL>DISASSEMBLY .

3. CHECK STEERING HEATER CONTROL MODULE  .

   Check the steering heater Control Module. Ref. to POWER ASSISTED SYSTEM (POWER STEERING)>STEERING HEATER SYSTEM>ELECTRICAL SPECIFICATION>STEERING HEATER Control Module .

   Is the steering heater Control Module OK?

   Yes:  Go to  4.

   No:  Replace the steering heater Control Module. Ref. to POWER ASSISTED SYSTEM (POWER STEERING)>STEERING WHEEL>DISASSEMBLY .

4. CHECK STEERING WHEEL  .

   Check the steering wheel. Ref. to POWER ASSISTED SYSTEM (POWER STEERING)>STEERING WHEEL>INSPECTION>STEERING WHEEL HEATER .

   Is the steering wheel OK?

   Yes:  Go to  5.

   No:  Replace the steering wheel. Ref. to POWER ASSISTED SYSTEM (POWER STEERING)>STEERING WHEEL .

5. CHECK HARNESS  .

   Check the harness between steering roll connector and steering heater Control Module.

   Connector & terminal 

   (ST11) No. 3 - (ST14) No. 1:

   (ST11) No. 4 - (ST14) No. 4:

   Is harness normal?

   Yes:  Go to  6.

   No:  Repair or replace the harness.

6. CHECK HARNESS  .

   Check the harness between steering heater switch and steering roll connector.

   Connector & terminal 

   (ST9) No. 1 - (ST11) No. 4:

   Is harness normal?

   Yes:  Go to  7.

   No:  Repair or replace the harness.

7. CHECK HARNESS  .

   Check the harness between steering heater switch and steering heater Control Module.

   Connector & terminal 

   (ST9) No. 2 - (ST14) No. 3:

   (ST9) No. 4 - (ST14) No. 2:

   Is harness normal?

   Yes:  Go to  8.

   No:  Repair or replace the harness.

8. CHECK ROLL CONNECTOR (HEATER)  .

   Check the steering roll connector. Ref. to AIRBAG SYSTEM>ROLL CONNECTOR>INSPECTION .

   Is the result of inspection OK?

   Yes:  Go to  9.

   No:  Replace the steering roll connector. Ref. to AIRBAG SYSTEM>ROLL CONNECTOR .

9. CHECK HARNESS  .

   Measure the resistance between connector of steering roll connector and body ground and between relay holder and body ground.

   Connector & terminal 

   (i289) No. 2 - Chassis ground:

   (i280) No. 3 - Chassis ground:

   Is the resistance less than 10 Ω?

   Yes:  Go to  10.

   No:  Repair or replace the harness.

10. CHECK HARNESS  .

    Check the harness between relay holder and steering roll connector.

    Connector & terminal 

    (i280) No. 1 - (i289) No. 4:

    Is harness normal?

    Yes:  Go to  11.

    No:  Repair or replace the harness.

11. CHECK FUSE  .
    1. Turn the ignition switch to OFF.
    2. Check the fuse on the upstream of the steering heater.

    Is the fuse OK?

    Yes:  Go to  12.

    No:  Replace the fuse.

12. CHECK RELAY  .

    Check the steering heater relay. Ref. to POWER ASSISTED SYSTEM (POWER STEERING)>RELAY AND FUSE .

    Is the steering heater relay OK?

    Yes:  Go to  13.

    No:  Replace the steering heater relay.

13. CHECK BATTERY VOLTAGE  .

    Measure the battery voltage.

    Is the battery OK?

    Yes:  It is possible that temporary poor contact occurs. Restore the parts and check it again.

    No:  Check the battery. Ref. to STARTING/CHARGING SYSTEMS (H4DOTC)>BATTERY>INSPECTION .