Wipers Operate When It Is Not Raining

Wiring diagram: 

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

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .

   Using the Subaru Select Monitor, read the DTC of body integrated unit, combination meter, VDC, and CAN system. Ref. to COMMON (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is a DTC detected for each system?

   Yes:  Perform a check according to the DTC.

   No:  Go to  2.

2. CHECK DTC  .

   Read the DTCs for rain/light sensor using the Subaru Select Monitor. Ref. to AUTOMATIC LIGHT AND WIPER (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC detected?

   Yes:  Perform a check according to the DTC.

   No:  Go to  3.

3. CHECK CUSTOMIZE SETTING  .

   Display the data of [Auto Wiper/INT Setting] using Subaru Select Monitor. Ref. to AUTOMATIC LIGHT AND WIPER (DIAGNOSTICS)>CUSTOMIZE . Ref. to BODY CONTROL (DIAGNOSTICS)>DATA MONITOR .

   Is the customize setting set to AUTO mode?

   Yes:  Go to  4.

   No:  Set to AUTO mode on the customize setting.

4. CHECK DATA MONITOR (COMBINATION SWITCH (WIPER))  .
   1. Display the data of [Front wiper Low switch input], [Front wiper High switch input] and [Front wiper AUTO switch input] using Subaru Select Monitor.
   2. Operate the combination switch (wiper), and read the data of the combination switch (wiper).
   3. Set the switch to AUTO and check the combination switch (wiper) display.

   Is only the data display [Front wiper AUTO switch input] turned ON?

   Yes:  Go to  5.

   No:  Perform inspection of the harness and combination switch (wiper).

5. CHECK HARNESS BETWEEN BODY INTEGRATED UNIT AND COMBINATION SWITCH (WIPER)  .
   1. Turn the ignition switch to OFF, and disconnect the connectors of body integrated unit and combination switch (wiper).
   2. Check the harness between body integrated unit and combination switch (wiper).

      Connector & terminal 

      (i81) No. 17 - (i69) No. 4:

      (i171) No. 21 - (i69) No. 4:

      (i81) No. 1 - (i69) No. 3:

      (i81) No. 21 - (i69) No. 9:

   Is the inspection result OK?

   Yes:  Go to  6.

   No:  Repair or replace the harness.

6. CHECK COMBINATION SWITCH (WIPER) UNIT  .

   Perform inspection of the combination switch (wiper). Ref. to WIPER AND WASHER SYSTEMS>COMBINATION SWITCH (WIPER)>INSPECTION>INSPECTION OF SWITCH UNIT .

   Is the inspection result of combination switch (wiper) OK?

   Yes:  Go to  7.

   No:  Replace the combination switch (wiper).

7. CHECK DATA MONITOR (WIPER OUTPUT SIGNAL)  .
   1. Turn the ignition switch to ON.
   2. Display the data of [Front wiper Low output] and [Front wiper High output] using Subaru Select Monitor. Ref. to AUTOMATIC LIGHT AND WIPER (DIAGNOSTICS)>DATA MONITOR .
   3. Wipe off the rain sensor detection surface.

   Are the data of [Front wiper Low output] and [Front wiper High output] ON?

   Yes:  Replace the sensor assembly rain.

   No:  Rain sensor detection surface is dirty.