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Home >> Lexus >> 2021 >> RC 350 Base, AWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Heated Glass/Defoggers >> Window Defogger System - Diagnostics & Symptom Tests >> Window Defogger System >> Rear Window Defogger System does not Operate [09/2014 - ] >> Procedure

Rear Window Defogger System does not Operate [09/2014 - ]: Procedure

  1. CHECK AIR CONDITIONING SYSTEM 
    1. Check the air conditioning system.

      HINT: 

      Both the window defogger system operation signal and air conditioning system operation signal are transmitted to the air conditioning amplifier assembly via the same communication line.

      OK

      The air conditioning system operates normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    GO TO AIR CONDITIONING SYSTEM. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2014 - 10/2015]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [10/2015 - 11/2017]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2017 - ] 

    Result: 

    OK 

    See step  2

  2. PERFORM ACTIVE TEST USING TECHSTREAM 
    1. Connect the Techstream to the DLC3.
    2. Turn the engine switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Air Conditioner / Active Test.
    5. Perform the Active Test according to the display on the Techstream.

      Body Electrical > Air Conditioner > Active Test 

      Tester Display Measurement Item Control Range Diagnostic Note
      Defogger Relay (Rear) Back window glass (rear window defogger wire) OFF or ON -

      Body Electrical > Air Conditioner > Active Test 

      Tester Display
      Defogger Relay (Rear)

      OK

      The rear window defogger system operates normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    See step  4

    Result: 

    OK 

    See step  3

  3. REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY 
    1. Replace the air conditioning amplifier assembly with a new or known good one.

      Refer to REMOVAL [09/2014 - ]

    2. Check that the window defogger system operates normally.

      Refer to OPERATION CHECK [09/2014 - ] 

      OK

      The window defogger system operates normally.

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    END (AIR CONDITIONING AMPLIFIER ASSEMBLY WAS DEFECTIVE) 

    Result: 

    NG 

    REPLACE AIR CONDITIONING CONTROL ASSEMBLY. Refer to  REMOVAL [09/2014 - ] 

  4. CHECK SEMICONDUCTOR POWER INTEGRATION ECU 
    1. Using a voltmeter, check the signal reading of the semiconductor pwr integration ECU.

      Refer to ON-VEHICLE INSPECTION [09/2014 - ]

      OK

      Output signal reading is normal.

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    INSPECT SEMICONDUCTOR POWER INTEGRATION ECU (RESULTS OF SIGNAL READING CHECK). Refer to  PROCEDURE - Step 2 

    Result: 

    OK 

    See step  5

  5. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU POWER SOURCE AND BODY GROUND) 
    1. Remove the semiconductor pwr integration ECU from the No. 2 engine room relay block and No. 2 junction block assembly.

      Refer to REMOVAL [09/2014 - ]

      GTY462739Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component without semiconductor pwr integration ECU
      (No. 2 Engine Room Relay Block and No. 2 Junction Block Assembly)      		 - -
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      2B-1 (BATT) - Body ground Always 11 to 14 V
      2A-1 (ALT) - Body ground Always 11 to 14 V
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      2D-14 (GND1) - Body ground Always Below 1 Ω
      2G-5 (GND2) - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  6

  6. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - AIR CONDITIONING AMPLIFIER ASSEMBLY) 
    1. Disconnect the O9 air conditioning amplifier assembly connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      O9-25 (RDEF) - 2D-5 (-S) Always Below 1 Ω
      O9-25 (RDEF) or 2D-5 (-S) - Body ground Always 10 kΩ or higher

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  7

  7. CHECK SEMICONDUCTOR POWER INTEGRATION ECU 
    1. Install the semiconductor pwr integration ECU.

      Refer to INSTALLATION [09/2014 - ]

    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      O9-25 (RDEF) - Body ground Engine switch on (IG), rear window defogger switch off 11 to 14 V
      GTY520696Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Air Conditioning Amplifier Assembly)

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    OK 

    See step  8

  8. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY 
    1. Reconnect the O9 air conditioning amplifier assembly connector.
    2. Measure the voltage according to the value(s) in the table below.
      GTY503185Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Component with harness connected
      (Air Conditioning Amplifier Assembly)

      Standard Voltage

      Tester Connection Condition Specified Condition
      O9-25 (RDEF) - O9-1 (GND) Engine switch on (IG), rear window defogger switch on Below 2.2 V
      O9-25 (RDEF) - O9-1 (GND) Engine switch on (IG), rear window defogger switch off 11 to 14 V

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    OK 

    See step  9

  9. CHECK HARNESS AND CONNECTOR (SEMICONDUCTOR PWR INTEGRATION ECU - BACK WINDOW GLASS (REAR WINDOW DEFOGGER WIRE)) 
    1. Disconnect the YU1 back window glass (rear window defogger wire) connector.
    2. Disconnect the 2C semiconductor pwr integration ECU connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      2C-1 (L) - YU1-2 Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

    Result: 

    OK 

    See step  10

  10. CHECK SEMICONDUCTOR POWER INTEGRATION ECU 
    1. Reconnect the 2C semiconductor pwr integration ECU connector.
    2. Measure the voltage according to the value(s) in the table below.

      Standard Voltage

      Tester Connection Condition Specified Condition
      YU1-2 - Body ground Engine switch on (IG), rear window defogger switch on 11 to 14 V
      YU1-2 - Body ground Engine switch on (IG), rear window defogger switch off Below 1 V
      GTY508711Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      *a Front view of wire harness connector
      (to Back Window Glass (Rear Window Defogger Wire))

      Result

      Proceed to
      OK
      NG

    Result: 

    NG 

    REPLACE SEMICONDUCTOR POWER INTEGRATION ECU. Refer to  REMOVAL [09/2014 - ] 

    Result: 

    OK 

    See step  11

  11. CHECK HARNESS AND CONNECTOR (BACK WINDOW GLASS (REAR WINDOW DEFOGGER WIRE) - BODY GROUND) 
    1. Disconnect the T29 back window glass (rear window defogger wire) connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance

      Tester Connection Condition Specified Condition
      T29-1 - Body ground Always Below 1 Ω

      Result

      Proceed to
      OK
      NG

    Result: 

    OK 

    REPAIR OR REPLACE BACK WINDOW GLASS (REAR WINDOW DEFOGGER WIRE). Refer to  REMOVAL [09/2014 - ] 

    Result: 

    NG 

    REPAIR OR REPLACE HARNESS OR CONNECTOR 

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