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Check Wiper Interlock Headlight System

WARNING: This page is about a different car, the 2022 Subaru WRX. However, it is still accessible from the selected car via links, so may be relevant.

Wiring diagram: 

Front wiper and washer system Ref. to WIRING SYSTEM>FRONT WIPER AND WASHER SYSTEM>WIRING DIAGRAM

G14612342Courtesy of SUBARU OF AMERICA, INC.
  1. AUTO HEADLIGHT SYSTEM CHECK  .
    1. Turn the ignition switch to ON.
    2. Check the operation of auto headlight system.

    Is the system normal?

    Yes  : Go to  2.

    No  : Check and repair the auto headlight system. Ref. to LIGHTING SYSTEM>HEADLIGHT SYSTEM>INSPECTION>CHECK HEADLIGHT SYSTEM 

  2. CHECK LIGHT CONTROL SENSOR  .

    Using Subaru Select Monitor, display data of [Wiper Link Auto Light Setup] in [Customize] of [Body Control]. Ref. to BODY CONTROL (DIAGNOSTICS)>CUSTOMIZE

    Is the setting [ON]?

    Yes  : Go to  3.

    No  : Turn the setting to [ON].

  3. CHECK DIAGNOSTIC TROUBLE CODE (DTC)  .
    1. Turn the ignition switch to ON and wait for at least 10 seconds.
    2. Read DTCs of the following items using the Subaru Select Monitor. Ref. to LAN SYSTEM (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)
      • [Body Control]
      • [Front Relay Control Module]

    Is DTC displayed?

    Yes  : Perform the diagnosis for the displayed DTCs.

    No  : Go to  4.

  4. CHECK FRONT RELAY CONTROL MODULE  .

    Using Subaru Select Monitor, display data of [F Wiper (RTN) Input] in [Data Monitor] of [Front Relay Control Module]. Ref. to COMMON (DIAGNOSTICS)>DATA MONITOR

    Does the display switch between [OFF] ←→ [ON] when the combination switch (wiper) is operated OFF ←→ INT/LO/HI?

    Yes  : Go to  5.

    No  : Go to  6.

  5. CHECK BODY INTEGRATED UNIT  .

    Using Subaru Select Monitor, display data of [Fr wiper input] in [Data Monitor] of [Body Control]. Ref. to COMMON (DIAGNOSTICS)>DATA MONITOR

    Does the display switch between [OFF] ←→ [ON] when the combination switch (wiper) is operated OFF ←→ INT/LO/HI?

    Yes  : Check the light control sensor, and then repair or replace it if defective. Ref. to LIGHTING SYSTEM>LIGHT CONTROL SENSOR 

    No  : Check the body integrated unit and replace it if defective.

  6. CHECK FRONT RELAY CONTROL MODULE  .

    Measure the voltage between front relay control module connector and chassis ground.

    Connector & terminal 

    (B68) No. 13 (+) - Chassis ground (-):

    Does the voltage switch between OFF (less than 1 V) ←→ ON (9 - 16 V) when the combination switch (wiper) is operated OFF ←→ INT/LO/HI?

    Yes  : Check the front relay control module and replace it if defective.

    No  : Go to  7.

  7. CHECK HARNESS  .
    1. Turn the ignition switch to OFF.
    2. Disconnect the connectors of front wiper motor and front relay control module.
    3. Check the harness between the front wiper motor and the front relay control module.

      Connector & terminal 

      (B130) No. 1 - (B68) No. 13:

    Is the resistance less than 10 Ω?

    Yes  : Go to  8.

    No  : Repair or replace the defective part.

  8. CHECK HARNESS  .

    Check the harness between the front wiper motor connector and the chassis ground.

    Connector & terminal 

    (B130) No. 4 - Chassis ground:

    Is the resistance less than 10 Ω?

    Yes  : Go to  9.

    No  : Repair or replace the defective part.

  9. CHECK FRONT WIPER MOTOR  .

    Check the continuity between front wiper motor terminals.

    Connector & terminal 

    (B130) No. 1 - (B130) No. 5:

    Is there continuity?

    Yes  : Check the front relay control module and replace it if defective.

    No  : Replace the front wiper motor. Ref. to WIPER AND WASHER SYSTEMS>FRONT WIPER MOTOR AND LINK