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Home >> Lexus >> 2017 >> RC 350 Base, AWD >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Meter / Gauge System - Diagnostic Codes & Symptom Tests (1 Of 2) >> Meter / Gauge System >> DTC B1508: Short in Turn Signal / Hazard Flasher Circuit [10/2018 - ] >> Procedure

DTC B1508: Short in Turn Signal / Hazard Flasher Circuit [10/2018 - ]: Procedure

  1. CHECK LIGHTS 
    1. Inspect the illumination of each turn signal light.

      Result

      Result Proceed to
      All LH turn signal lights do not blink A
      All RH turn signal lights do not blink B

    Result: 

    B 

    See step  18

    Result: 

    A 

    See step  2

  2. CHECK LH SIDE LIGHTS (FRONT TURN SIGNAL LIGHT) 
    1. Disconnect the A36 headlight ECU sub-assembly LH connector.
    2. Operate the headlight dimmer switch assembly and check that the LH side turn signal lights other than the front turn signal light blink.

      HINT: 

      If the LH side turn signal lights blink, the headlight circuit is malfunctioning.

      Result

      Result Proceed to
      LH side turn signal lights blink A
      LH side turn signal lights do not blink B

    Result: 

    B 

    See step  5

    Result: 

    A 

    See step  3

  3. CHECK LH SIDE LIGHTS (HEADLIGHT UNIT ASSEMBLY LH) 
    1. Remove each headlight ECU sub-assembly, interchange the headlight unit assembly LH with RH and connect the connectors.

      Refer to DISASSEMBLY [10/2018 - ]

    2. Operate the headlight dimmer switch assembly and check that the LH side turn signal lights other than the front turn signal light blink.

      HINT: 

      If the LH side turn signal lights blink, the headlight unit assembly LH is malfunctioning.

      Result

      Result Proceed to
      LH side turn signal lights blink A
      LH side turn signal lights do not blink B

    Result: 

    B 

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY LH. Refer to  REMOVAL [10/2018 - ] 

    Result: 

    A 

    See step  4

  4. CHECK LH SIDE LIGHTS (HEADLIGHT UNIT ASSEMBLY LH) 
    1. Remove the headlight clearance LED unit LH.

      Refer to DISASSEMBLY [10/2018 - ]

    2. Install the headlight unit assembly LH.
    3. Operate the headlight dimmer switch assembly and check that the LH side turn signal lights other than the front turn signal light blink.

      HINT: 

      If the LH side turn signal lights blink, the headlight clearance LED unit LH is malfunctioning.

      Result

      Result Proceed to
      LH side turn signal lights blink A
      LH side turn signal lights do not blink B

    Result: 

    A 

    REPLACE HEADLIGHT CLEARANCE LED UNIT LH. Refer to  DISASSEMBLY [10/2018 - ] 

    Result: 

    B 

    REPLACE HEADLIGHT UNIT ASSEMBLY LH. Refer to  DISASSEMBLY [10/2018 - ] 

  5. CONFIRM MODEL 
    1. Choose the model to be inspected.

      Result

      Result Proceed to
      w/ Seat Position Memory System A
      w/o Seat Position Memory System B

    Result: 

    B 

    See step  10

    Result: 

    A 

    See step  6

  6. CHECK LH SIDE LIGHTS (SIDE TURN SIGNAL LIGHT) 
    1. Connect all other connectors in the same circuit.
    2. Disconnect the S12 outer mirror control ECU assembly LH connector.
    3. Operate the headlight dimmer switch assembly and check that the LH side turn signal lights other than the side turn signal light blink.

      HINT: 

      If the LH side turn signal lights blink, the side turn light circuit is malfunctioning.

      Result

      Result Proceed to
      LH side turn signal lights blink A
      LH side turn signal lights do not blink B

    Result: 

    B 

    See step  12

    Result: 

    A 

    See step  7

  7. CHECK LH SIDE LIGHTS (OUTER MIRROR CONTROL ECU ASSEMBLY LH) 
    1. Connect the S12 outer mirror control ECU assembly LH connector.
    2. Disconnect the S13 outer mirror control ECU assembly LH connector.
    3. Operate the headlight dimmer switch assembly and check that the LH side turn signal lights other than the side turn signal light blink.

      HINT: 

      If the LH side turn signal lights blink, the outer mirror control ECU assembly LH is malfunctioning.

      Result

      Result Proceed to
      LH side turn signal lights blink A
      LH side turn signal lights do not blink B

    Result: 

    A 

    REPLACE OUTER MIRROR CONTROL ECU ASSEMBLY LH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    B 

    See step  8

  8. CHECK HARNESS AND CONNECTOR (OUTER REAR VIEW MIRROR ASSEMBLY LH - OUTER MIRROR CONTROL ECU ASSEMBLY LH) 
    1. Disconnect the S7 outer rear view mirror assembly LH connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      S7-16 (B) or S13-16 (TRN+) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  9

  9. CHECK LH SIDE LIGHTS (SIDE TURN SIGNAL LIGHT ASSEMBLY LH) 
    1. Remove the side turn signal light assembly LH.

      Refer to REMOVAL [10/2018 - ]

    2. Connect the S7 outer rear view mirror assembly LH connector.
    3. Operate the headlight dimmer switch assembly and check that the LH side turn signal lights other than the side turn signal light blink.

      HINT: 

      If the LH side turn signal lights blink, the side turn signal light assembly LH is malfunctioning.

      Result

      Result Proceed to
      LH side turn signal lights blink A
      LH side turn signal lights do not blink B

    Result: 

    A 

    REPLACE SIDE TURN SIGNAL LIGHT ASSEMBLY LH. Refer to  REMOVAL [10/2018 - ] 

    Result: 

    B 

    REPLACE OUTER REAR VIEW MIRROR ASSEMBLY LH. Refer to  REMOVAL [10/2018 - ] 

  10. CHECK LH SIDE LIGHTS (SIDE TURN SIGNAL LIGHT) 
    1. Connect all other connectors in the same circuit.
    2. Disconnect the S7 outer rear view mirror assembly LH connector.
    3. Operate the headlight dimmer switch assembly and check that the LH side turn signal lights other than the side turn signal light blink.

      HINT: 

      If the LH side turn signal lights blink, the side turn light circuit is malfunctioning.

      Result

      Result Proceed to
      LH side turn signal lights blink A
      LH side turn signal lights do not blink B

    Result: 

    B 

    See step  12

    Result: 

    A 

    See step  11

  11. CHECK LH SIDE LIGHTS (SIDE TURN SIGNAL LIGHT ASSEMBLY LH) 
    1. Remove the side turn signal light assembly LH.

      Refer to REMOVAL [10/2018 - ]

    2. Connect the S7 outer rear view mirror assembly LH connector.
    3. Operate the headlight dimmer switch assembly and check that the LH side turn signal lights other than the side turn signal light blink.

      HINT: 

      If the LH side turn signal lights blink, the side turn signal light assembly LH is malfunctioning.

      Result

      Result Proceed to
      LH side turn signal lights blink A
      LH side turn signal lights do not blink B

    Result: 

    A 

    REPLACE SIDE TURN SIGNAL LIGHT ASSEMBLY LH. Refer to  REMOVAL [10/2018 - ] 

    Result: 

    B 

    REPLACE OUTER REAR VIEW MIRROR ASSEMBLY LH. Refer to  REMOVAL [10/2018 - ] 

  12. CHECK LH SIDE LIGHTS (WINDSHIELD WIPER SWITCH ASSEMBLY) 
    1. Connect all other connectors in the same circuit.
    2. Disconnect the O23 windshield wiper switch assembly connector.
    3. Operate the hazard warning signal switch (air conditioning control assembly) and check that the LH side turn signal lights blink.

      HINT: 

      If the LH side turn signal lights blink, the windshield wiper switch assembly is malfunctioning.

      Result

      Result Proceed to
      LH side turn signal lights blink A
      LH side turn signal lights do not blink B

    Result: 

    A 

    REPLACE WINDSHIELD WIPER SWITCH ASSEMBLY. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    B 

    See step  13

  13. CHECK LH SIDE LIGHTS (HAZARD WARNING SIGNAL SWITCH (AIR CONDITIONING CONTROL ASSEMBLY)) 
    1. Connect all other connectors in the same circuit.
    2. Disconnect the O64 hazard warning signal switch (air conditioning control assembly) connector.
    3. Operate the headlight dimmer switch assembly and check that the LH side turn signal lights blink.

      HINT: 

      If the LH side turn signal lights blink, the hazard warning signal switch (air conditioning control assembly) is malfunctioning.

      Result

      Result Proceed to
      LH side turn signal lights blink A
      LH side turn signal lights do not blink B

    Result: 

    A 

    REPLACE HAZARD WARNING SIGNAL SWITCH (AIR CONDITIONING CONTROL ASSEMBLY). Refer to  REMOVAL [09/2014 - ] 

    Result: 

    B 

    See step  14

  14. CHECK HARNESS AND CONNECTOR (ALL PARTS IN THE SAME CIRCUIT - COMBINATION METER ASSEMBLY) 
    1. Disconnect the O4 combination meter assembly connector.
    2. Disconnect the A36 headlight ECU sub-assembly LH connector.
    3. Disconnect the S12 outer mirror control ECU assembly LH connector.*1
    4. Disconnect the S7 outer rear view mirror assembly LH connector.*2
    5. Disconnect the O23 windshield wiper switch assembly connector.
    6. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      O4-11 (LL), A36-11 (TNS), S12-11 (TRNI)*1, S7-16 (B)*2, O23-1 (TRNL) or O64-6 (HFL) - Body ground Always 10 kΩ or higher
      1. *1: w/ Seat Position Memory System
      2. *2: w/o Seat Position Memory System

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  15

  15. CHECK LH SIDE LIGHTS (REAR TURN SIGNAL LIGHT) 
    1. Connect all other connectors in the same circuit.
    2. Disconnect the U41 rear combination light assembly LH connector.
    3. Operate the headlight dimmer switch assembly and check that the LH side turn signal lights other than the rear turn signal light blink.

      HINT: 

      If the LH side turn signal lights blink, the rear combination light assembly LH is malfunctioning.

      Result

      Result Proceed to
      LH side turn signal lights blink A
      LH side turn signal lights do not blink B

    Result: 

    B 

    See step  17

    Result: 

    A 

    See step  16

  16. INSPECT REAR COMBINATION LIGHT ASSEMBLY LH 
    1. Remove the rear combination light assembly LH.

      Refer to REMOVAL [10/2018 - ]

    2. Inspect the rear combination light assembly LH.

      Refer to INSPECTION [09/2014 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE REAR COMBINATION LIGHT CORD LH. Refer to  DISASSEMBLY [10/2018 - ] 

    Result: 

    NG 

    REPLACE REAR COMBINATION LIGHT ASSEMBLY LH. Refer to  REMOVAL [10/2018 - ] 

  17. CHECK HARNESS AND CONNECTOR (REAR COMBINATION LIGHT ASSEMBLY LH - COMBINATION METER ASSEMBLY) 
    1. Disconnect the O4 combination meter assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      O4-10 (TRNL) or U41-3 (TRN) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY 

    Refer to REMOVAL [09/2014 - ]

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

  18. CHECK RH SIDE LIGHTS (FRONT TURN SIGNAL LIGHT) 
    1. Disconnect the A7 headlight ECU sub-assembly RH connector.
    2. Operate the headlight dimmer switch assembly and check that the RH side turn signal lights other than the front turn signal light blink.

      HINT: 

      If the RH side turn signal lights blink, the headlight circuit is malfunctioning.

      Result

      Result Proceed to
      RH side turn signal lights blink A
      RH side turn signal lights do not blink B

    Result: 

    B 

    See step  21

    Result: 

    A 

    See step  19

  19. CHECK RH SIDE LIGHTS (HEADLIGHT UNIT ASSEMBLY RH) 
    1. Remove each headlight ECU sub-assembly, interchange the headlight unit assembly RH with LH and connect the connectors.

      Refer to DISASSEMBLY [10/2018 - ]

    2. Operate the headlight dimmer switch assembly and check that the RH side turn signal lights other than the front turn signal light blink.

      HINT: 

      If the RH side turn signal lights blink, the headlight unit assembly RH is malfunctioning.

      Result

      Result Proceed to
      RH side turn signal lights blink A
      RH side turn signal lights do not blink B

    Result: 

    B 

    REPLACE HEADLIGHT ECU SUB-ASSEMBLY RH. Refer to  REMOVAL [10/2018 - ] 

    Result: 

    A 

    See step  20

  20. CHECK RH SIDE LIGHTS (HEADLIGHT UNIT ASSEMBLY RH) 
    1. Remove each headlight clearance LED unit RH.

      Refer to DISASSEMBLY [10/2018 - ]

    2. Install the headlight clearance LED unit RH.
    3. Operate the headlight dimmer switch assembly and check that the RH side turn signal lights other than the front turn signal light blink.

      HINT: 

      If the RH side turn signal lights blink, the headlight clearance LED unit RH is malfunctioning.

      Result

      Result Proceed to
      RH side turn signal lights blink A
      RH side turn signal lights do not blink B

    Result: 

    A 

    REPLACE HEADLIGHT CLEARANCE LED UNIT RH. Refer to  DISASSEMBLY [10/2018 - ] 

    Result: 

    B 

    REPLACE HEADLIGHT UNIT ASSEMBLY RH. Refer to  DISASSEMBLY [10/2018 - ] 

  21. CONFIRM MODEL 
    1. Choose the model to be inspected.

      Result

      Result Proceed to
      w/ Seat Position Memory System A
      w/o Seat Position Memory System B

    Result: 

    B 

    See step  26

    Result: 

    A 

    See step  22

  22. CHECK RH SIDE LIGHTS (SIDE TURN SIGNAL LIGHT) 
    1. Connect all other connectors in the same circuit.
    2. Disconnect the R12 outer mirror control ECU assembly RH connector.
    3. Operate the headlight dimmer switch assembly and check that the RH side turn signal lights other than the side turn signal light blink.

      HINT: 

      If the RH side turn signal lights blink, the side turn light circuit is malfunctioning.

      Result

      Result Proceed to
      RH side turn signal lights blink A
      RH side turn signal lights do not blink B

    Result: 

    B 

    See step  28

    Result: 

    A 

    See step  23

  23. CHECK RH SIDE LIGHTS (OUTER MIRROR CONTROL ECU ASSEMBLY RH) 
    1. Connect the R12 outer mirror control ECU assembly RH connector.
    2. Disconnect the R13 outer mirror control ECU assembly RH connector.
    3. Operate the headlight dimmer switch assembly and check that the RH side turn signal lights other than the side turn signal light blink.

      HINT: 

      If the RH side turn signal lights blink, the outer mirror control ECU assembly RH is malfunctioning.

      Result

      Result Proceed to
      RH side turn signal lights blink A
      RH side turn signal lights do not blink B

    Result: 

    A 

    REPLACE OUTER MIRROR CONTROL ECU ASSEMBLY RH. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    B 

    See step  24

  24. CHECK HARNESS AND CONNECTOR (OUTER REAR VIEW MIRROR ASSEMBLY RH - OUTER MIRROR CONTROL ECU ASSEMBLY RH) 
    1. Disconnect the R7 outer rear view mirror assembly RH connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      R7-16 (B) or R13-16 (TRN+) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  25

  25. CHECK RH SIDE LIGHTS (SIDE TURN SIGNAL LIGHT ASSEMBLY RH) 
    1. Remove the side turn signal light assembly RH.

      Refer to REMOVAL [10/2018 - ]

    2. Connect the R7 outer rear view mirror assembly RH connector.
    3. Operate the headlight dimmer switch assembly and check that the RH side turn signal lights other than the side turn signal light blink.

      HINT: 

      If the RH side turn signal lights blink, the side turn signal light assembly RH is malfunctioning.

      Result

      Result Proceed to
      RH side turn signal lights blink A
      RH side turn signal lights do not blink B

    Result: 

    A 

    REPLACE SIDE TURN SIGNAL LIGHT ASSEMBLY RH. Refer to  REMOVAL [10/2018 - ] 

    Result: 

    B 

    REPLACE OUTER REAR VIEW MIRROR ASSEMBLY RH. Refer to  REMOVAL [10/2018 - ] 

  26. CHECK RH SIDE LIGHTS (SIDE TURN SIGNAL LIGHT) 
    1. Connect all other connectors in the same circuit.
    2. Disconnect the R7 outer rear view mirror assembly RH connector.
    3. Operate the headlight dimmer switch assembly and check that the RH side turn signal lights other than the side turn signal light blink.

      HINT: 

      If the RH side turn signal lights blink, the side turn light circuit is malfunctioning.

      Result

      Result Proceed to
      RH side turn signal lights blink A
      RH side turn signal lights do not blink B

    Result: 

    B 

    See step  28

    Result: 

    A 

    See step  27

  27. CHECK RH SIDE LIGHTS (SIDE TURN SIGNAL LIGHT ASSEMBLY RH) 
    1. Remove the side turn signal light assembly RH.

      Refer to REMOVAL [10/2018 - ]

    2. Connect the R7 outer rear view mirror assembly RH connector.
    3. Operate the headlight dimmer switch assembly and check that the RH side turn signal lights other than the side turn signal light blink.

      HINT: 

      If the RH side turn signal lights blink, the side turn signal light assembly RH is malfunctioning.

      Result

      Result Proceed to
      RH side turn signal lights blink A
      RH side turn signal lights do not blink B

    Result: 

    A 

    REPLACE SIDE TURN SIGNAL LIGHT ASSEMBLY RH. Refer to  REMOVAL [10/2018 - ] 

    Result: 

    B 

    REPLACE OUTER REAR VIEW MIRROR ASSEMBLY RH. Refer to  REMOVAL [10/2018 - ] 

  28. CHECK RH SIDE LIGHTS (WINDSHIELD WIPER SWITCH ASSEMBLY) 
    1. Connect all other connectors in the same circuit.
    2. Disconnect the O23 windshield wiper switch assembly connector.
    3. Operate the hazard warning signal light switch (air conditioning control assembly) and check that the RH side turn signal lights blink.

      HINT: 

      If the RH side turn signal lights blink, the windshield wiper switch assembly is malfunctioning.

      Result

      Result Proceed to
      RH side turn signal lights blink A
      RH side turn signal lights do not blink B

    Result: 

    A 

    REPLACE WINDSHIELD WIPER SWITCH ASSEMBLY. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    B 

    See step  29

  29. CHECK HARNESS AND CONNECTOR (ALL PARTS IN THE SAME CIRCUIT - COMBINATION METER ASSEMBLY) 
    1. Disconnect the O4 combination meter assembly connector.
    2. Disconnect the A7 headlight ECU sub-assembly RH connector.
    3. Disconnect the R12 outer mirror control ECU assembly RH connector.*1
    4. Disconnect the R7 outer rear view mirror assembly RH connector.*2
    5. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      O4-7 (LR), A7-11 (TNS), R12-11 (TRNI)*1, R7-16 (B)*2, or O23-1 (TRNR) - Body ground Always 10 kΩ or higher
      1. *1: w/ Seat Position Memory System
      2. *2: w/o Seat Position Memory System

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  30

  30. CHECK RH SIDE LIGHTS (REAR TURN SIGNAL LIGHT) 
    1. Connect all other connectors in the same circuit.
    2. Disconnect the U41 rear combination light assembly RH connector.
    3. Operate the headlight dimmer switch assembly and check that the RH side turn signal lights other than the rear turn signal light blink.

      HINT: 

      If the RH side turn signal lights blink, the rear combination light assembly RH is malfunctioning.

      Result

      Result Proceed to
      RH side turn signal lights blink A
      RH side turn signal lights do not blink B

    Result: 

    B 

    See step  32

    Result: 

    A 

    See step  31

  31. INSPECT REAR COMBINATION LIGHT ASSEMBLY RH 
    1. Remove the rear combination light assembly RH.

      Refer to REMOVAL [10/2018 - ]

    2. Inspect the rear combination light assembly RH.

      Refer to DISASSEMBLY [10/2018 - ]

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE REAR COMBINATION LIGHT CORD RH 

    Refer to DISASSEMBLY [10/2018 - ]

    Result: 

    NG 

    REPLACE REAR COMBINATION LIGHT ASSEMBLY RH 

    Refer to REMOVAL [10/2018 - ]

  32. CHECK HARNESS AND CONNECTOR (REAR COMBINATION LIGHT ASSEMBLY RH - COMBINATION METER ASSEMBLY) 
    1. Disconnect the O4 combination meter assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      O4-5 (TRNR) or U41-4 (TRN) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPLACE COMBINATION METER ASSEMBLY. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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