Check Turn Signal Light 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:

Turn signal and hazard light system Ref. to WIRING SYSTEM>TURN SIGNAL LIGHT AND HAZARD LIGHT SYSTEM>WIRING DIAGRAM

Courtesy of SUBARU OF AMERICA, INC.

Courtesy of SUBARU OF AMERICA, INC.

Courtesy of SUBARU OF AMERICA, INC.

NOTE:

Operate the appropriate switch according to the inspection condition.

CHECK TURN SIGNAL LIGHT OPERATION .
1. Turn the ignition switch to ON.
2. Turn the turn signal light switch LH and RH to ON.
Does the turn signal light blink?

Yes : The turn signal light system is normal.

No : Go to 2.
CHECK BULB .
Check the hazard (turn signal) light bulb.

Is the bulb normal?

Yes : Go to 3.

No : Replace the hazard (turn signal) light bulb.
CHECK POWER SUPPLY .
Using the Subaru Select Monitor, display the following items in the [Data monitor] of [Body Control]. Ref. to COMMON (DIAGNOSTICS)>DATA MONITOR
- [BATT voltage (control)]
- [BATT voltage (BACKUP)]
- [IGN voltage]
Is the voltage 9 - 16 V?

Yes : Go to 4.

No : Check the body integrated unit and replace it if defective.
- Inspection: Ref. to BODY CONTROL (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE
- Replacement: Ref. to BODY CONTROL/COMMUNICATION SYSTEM>BODY INTEGRATED UNIT
CHECK DTC .
1. Turn the ignition switch to ON and wait for at least 10 seconds.
2. Read the DTC of [Body Control] using the Subaru Select Monitor. Ref. to COMMON (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)
Is DTC displayed?

Yes : Perform the diagnosis for the displayed DTCs. Ref. to BODY CONTROL (DIAGNOSTICS)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST

No : Go to 5.
CHECK CURRENT DATA .
Using the Subaru Select Monitor, display the following items in the [Data monitor] of [Body Control]. Ref. to COMMON (DIAGNOSTICS)>DATA MONITOR
- [Left turn signal input]
- [Right turn signal input]
- [Turn Signal Deep Push Input]
Does the display change as [OFF] ←→ [ON], when the turn signal switch is turned from OFF to ON?

Yes : Go to 6.

No : Go to 7.
CHECK HARNESS .
1. Disconnect the connectors of body integrated unit and each turn signal light.
2. Check the harness between body integrated unit and each turn signal light.
  Connector & terminal
  
  Front turn signal light RH (model without SRH)
  
  (B71) No. 2 - (B121) No. 5:
  
  Front turn signal light LH (model without SRH)
  
  (B71) No. 8 - (B122) No. 5:
  
  Front turn signal light RH (model with SRH)
  
  (B71) No. 2 - (B121) No. 3:
  
  Front turn signal light LH (model with SRH)
  
  (B71) No. 8 - (B122) No. 3:
  
  Side turn signal light RH
  
  (i81) No. 5 - (Df55) No. 2:
  
  Side turn signal light LH
  
  (i81) No. 2 - (Df56) No. 2:
  
  Rear turn signal light RH
  
  (i81) No. 5 - (R131) No. 3:
  
  Rear turn signal light LH
  
  (i81) No. 2 - (L131) No. 3:
Is harness normal?

Yes : Go to 7.

No : Repair or replace the defective part.
CHECK TURN SIGNAL SWITCH .
Check the turn signal switch. Ref. to LIGHTING SYSTEM>COMBINATION SWITCH (LIGHT)>INSPECTION

Is the turn signal switch OK?

Yes : Go to 8.

No : Replace the combination switch (light). Ref. to LIGHTING SYSTEM>COMBINATION SWITCH (LIGHT)
CHECK HARNESS .
1. Turn the ignition switch to OFF.
2. Disconnect the connectors of body integrated unit and combination switch (light).
3. Check the harness between body integrated unit and combination switch (light).
  Connector & terminal
  
  (i82) No. 33 - (i131) No. 14:
  
  (i82) No. 38 - (i131) No. 15:
  
  (i82) No. 22 - (i131) No. 12:
Is harness normal?

Yes : Go to 9.

No : Repair or replace the defective part.
CHECK HARNESS .
Check the harness between the combination switch (light) connector and the chassis ground.

Connector & terminal

(i131) No. 13 - Chassis ground:

Is the resistance less than 10 Ω?

Yes : Check the body integrated unit and replace it if defective.
- Inspection: Ref. to BODY CONTROL (DIAGNOSTICS)>BASIC DIAGNOSTIC PROCEDURE
- Replacement: Ref. to BODY CONTROL/COMMUNICATION SYSTEM>BODY INTEGRATED UNIT
No : Repair or replace the defective part.