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Home >> Lexus >> 2008 >> LS 460 >> Repair and Diagnosis >> Body & Frame >> Windows >> Windshield/WINDOWGLASS >> Windshield Deicer System >> Windshield Deicer Does Not Operate >> Inspection Procedure
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Inspection Procedure

  1. CHECK OPERATION (ENGINE START) 
    1. Check that the engine starts normally.

      OK: Engine starts normally. 

    NG: GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START  (See HOW TO PROCEED WITH TROUBLESHOOTING )

    OK: Go to next step 

  2. PERFORM ACTIVE TEST BY TECHSTREAM (DEICER RELAY) 
    1. Select the Active Test, using the Techstream to generate a control command, and then check that the windshield deicer operates.

      Air Conditioner 

      ACTIVE TEST TABLE

      Tester Display Test Part Control Range Diagnostic Note
      Deicer Relay (Front) Deicer relay operation OFF/ON -

      Result 

      RESULT TABLE

      Result Proceed to
      Windshield deicer operates normally (w/ Multi-display) A
      Windshield deicer operates normally (w/o Multi-display) B
      Windshield deicer does not operate C

    B: Go to step   4 

    C: Go to step   5 

    A: Go to next step 

  3. CHECK MULTI-DISPLAY (OPERATION) 
    1. Temporarily replace the multi-display with a new or normally functioning one (see REMOVAL ).
    2. Check that the malfunction disappears.

      OK: Malfunction disappears. 

    NG: REPLACE AIR CONDITIONING AMPLIFIER  (See REMOVAL )

    OK: REPLACE MULTI-DISPLAY  (See REMOVAL )

  4. CHECK INTEGRATION CONTROL AND PANEL (OPERATION) 
    1. Temporarily replace the integration control and panel with a new or normally functioning one (see REMOVAL ).
    2. Check that the malfunction disappears.

      OK: Malfunction disappears. 

    NG: REPLACE AIR CONDITIONING AMPLIFIER  (See REMOVAL )

    OK: REPLACE INTEGRATION CONTROL AND PANEL  (See REMOVAL )

  5. INSPECT FUSE (DEICER) 
    1. Remove the DEICER fuse from the engine room No. 2 relay block.
    2. Measure the resistance of the fuse.

      Standard resistance 

      RESISTANCE SPECIFICATION TABLE

      Tester Connection Condition Specified Condition
      DEICER fuse Always Below 1 Ω

    NG: REPLACE FUSE 

    OK: Go to next step 

  6. INSPECT DEICER RELAY 
    1. Remove the deicer relay from the No. 3 relay block.
      Fig 1: Identifying Deicer Relay
      G04950839Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      RESISTANCE SPECIFICATION TABLE

      Tester Connection Condition Specified Condition
      3 - 5 When battery voltage is not applied between terminals 10 kΩ or higher
      When battery voltage is applied to terminals 1 and 2 Below 1 Ω

    NG: REPLACE DEICER RELAY 

    OK: Go to next step 

  7. CHECK HARNESS AND CONNECTOR (DEICER RELAY - FRONT LIGHT ECU AND BATTERY) 
    1. Remove the deicer relay from the No. 3 relay block.
    2. Disconnect the A51 front light ECU connector.
    3. Measure the voltage according to the value(s) in the table below.

      Standard voltage 

      VOLTAGE SPECIFICATION TABLE

      Tester Connection Switch Condition Specified Condition
      Deicer relay terminal 1 - Body ground Engine switch on (IG) 11 to 14 V
      Deicer relay terminal 5 - Body ground Always 11 to 14 V
    4. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      RESISTANCE SPECIFICATION TABLE

      Tester Connection Condition Specified Condition
      Deicer relay terminal 2 - A51-13 (FDEF) Always Below 1 Ω
      Fig 2: Identifying A51 Front Light ECU Connector
      G04952234Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  8. CHECK HARNESS AND CONNECTOR (DEICER RELAY - WINDSHIELD DEICER WIRE) 
    1. Remove the deicer relay from the No. 3 relay block.
    2. Disconnect the A30 windshield deicer wire connector.
    3. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      RESISTANCE SPECIFICATION TABLE

      Tester Connection Condition Specified Condition
      A30-1 (B2) - Deicer relay terminal 3 Always Below 1 Ω
      A30-2 (B) - Deicer relay terminal 3 Always Below 1 Ω
      Deicer relay terminal 3 - Body ground Always 10 kΩ or higher
      Fig 3: Identifying A30 Windshield Deicer Wire Connector
      G04952235Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  9. CHECK HARNESS AND CONNECTOR (WINDSHIELD DEICER WIRE - BODY GROUND) 
    1. Disconnect the A30 windshield deicer wire connector.
    2. Measure the resistance according to the value(s) in the table below.

      Standard resistance 

      RESISTANCE SPECIFICATION TABLE

      Tester Connection Condition Specified Condition
      A30-3 (E) - Body ground Always Below 1 Ω
      Fig 4: Identifying Windshield Deicer Connector A30
      G04952180Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  10. CHECK FRONT LIGHT ECU (OPERATION) 
    1. Temporarily replace the front light ECU with a new or normally functioning one.
    2. Check that the malfunction disappears.

      OK: Malfunction disappears. 

    NG: REPLACE AIR CONDITIONING AMPLIFIER  (See REMOVAL )

    OK: REPLACE FRONT LIGHT ECU 

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