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Home › Lexus › 2004 › RX 330 FWD › Repair and Diagnosis › External Pages › Different car › Section 564 (Lighting) › Lighting System › Headlight Relay Circuit › Inspection Procedure

Inspection Procedure

WARNING: This page is about a different car, the 2008 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.

HINT:

Start the inspection from step 1 when using the intelligent tester, and start from step  2 when not using the intelligent tester.

  1. PERFORM ACTIVE TEST BY INTELLIGENT TESTER 
    1. Connect the intelligent tester to the DLC3.
    2. Turn the ignition switch to ON position and press the intelligent tester main switch ON.
    3. Select the item below in the ACTIVE TEST and then check that the relay operates.

      BODY No. 1 

      ITEM CONDITION CHART

      Item Test Details Diagnostic Note
      HEAD LIGHT Turn Headlight relay ON/OFF -

    NG: Go to step   2 

    OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN  PROBLEM SYMPTOMS TABLE  

  2. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT) 
    1. Disconnect the connector from the J/B No. 2 (power distributor).
    2. Measure the voltage according to the value(s) in the table below.

      Voltage 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester connection Condition Specified value
      2I-1 (+B) - Body ground Always 10 to 14 V
      Fig 1: Identifying J/B No.2 (Power Distributor) Connector Terminals
      G05273782Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next step 

  3. CHECK MODE MONITOR TERMINAL (H-LP R RELAY, H-LP L RELAY) 
    1. Preparation
      1. Connect the connector.
      2. Remove the cover of the fusible link block assembly.
      3. Set the vehicle to the following condition.
        • Ignition switch ON.
        • Headlight dimmer switch LO.
        • Light control switch ON.
    2. Check voltage
      1. Measure the voltage between the Mode Monitor Terminal and body ground.

        Result 

        RESULT REFERENCE CHART

        Condition Proceed to
        6.3 +- 2V A
        Approx. 1 V B
        Fig 2: Identifying Mode Monitor Terminal
        G05201886Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    B: Go to step  9

    A: Go to Next step 

  4. INSPECT JUNCTION BLOCK NO.2 (HEAD LIGHT RELAY) 
    1. Turn the ignition switch to OFF position.
    2. Remove the J/B No.2.
    3. Inspect the H-LP R.
      Fig 3: Identifying Junction Block No.2 (Head Light Relay)
      G05273784Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Connect the positive battery lead to terminal +B of the J/B No.2 and the negative lead to terminal SGND, PGND.
        ECU CONNECTOR TERMINALS AND SYMBOLS SPECIFIED CONDITION

        Symbols (terminals No.) Connection
        +B (2I-1) - SGND (2H-13), PGND (2F-1) Positive - Negative
      2. Measure the voltage according to the value(s) in the table below.

        Voltage 

        TESTER CONNECTION SPECIFIED CONDITION

        Tester connection Specified Condition
        LPR (2A-3) - Battery negative terminal Below 1 V
      3. Connect the battery negative lead to terminal HRLY of the J/B No.2.
        ECU CONNECTOR TERMINALS AND SYMBOLS SPECIFIED CONDITION

        Symbols (terminals No.) Connection
        HRLY (2H-8) Negative
      4. Measure the voltage according to the value(s) in the table below.

        Voltage 

        TESTER CONNECTION SPECIFIED CONDITION

        Tester connection Specified Condition
        LPR (2A-3) - Battery negative terminal 10 to 14 V
    4. Inspect the H-LP L.
      1. Connect the positive battery lead to terminal +B of the J/B No.2 and the negative lead to terminal SGND, PGND.
        ECU CONNECTOR TERMINALS AND SYMBOLS SPECIFIED CONDITION

        Symbols (terminals No.) Connection
        +B (2I-1) - SGND (2H-13), PGND (2F-1) Positive - Negative
      2. Measure the voltage according to the value(s) in the table below.

        Voltage 

        TESTER CONNECTION SPECIFIED CONDITION

        Tester connection Specified Condition
        LPL (2A-2) - Battery negative terminal Below 1 V
      3. Connect the battery negative lead to terminal HRLY of the J/B No.2.
        ECU CONNECTOR TERMINALS AND SYMBOLS SPECIFIED CONDITION

        Symbols (terminals No.) Connection
        HRLY (2H-8) Negative
      4. Measure the voltage according to the value(s) in the table below.

        Voltage 

        TESTER CONNECTION SPECIFIED CONDITION

        Tester connection Specified Condition
        LPL (2A-2) - Battery negative terminal 10 to 14 V

    NG: REPLACE JUNCTION BLOCK NO.2 

    OK: Go to Next step 

  5. CHECK HARNESS AND CONNECTOR (HRLY SIGNAL CIRCUIT) 
    1. Disconnect the connector from the instrument panel J/B.
      Fig 4: Identifying Instrument Panel Junction Block Assembly Front Side Connector Terminals
      G05273785Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      Reconnect the J/B No. 2 connector.

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

      Voltage 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester connection Condition Specified value
      10-3 - Body ground Always 10 to 14 V

    NG: Go to step  8

    OK: Go to Next step 

  6. CHECK HARNESS AND CONNECTOR (J/B NO. 2 - BULB) 
    1. Disconnect the connector from the J/B No. 2 (power distributor).
      Fig 5: Identifying J/B No. 2 (Power Distributor) Connector Terminals
      G05273786Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the connectors from the headlight bulbs.
    3. Measure the resistance according to the value(s) in the table below.

      Resistance 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester connection Condition Specified value
      2A-2 (LPL) - H5-2 (Headlight LH) Always Below 1 Ω
      2A-3 (LPL) - H9-2 (Headlight RH) Always Below 1 Ω
      2A-2 (LPL) - Body ground Always 10 kΩ or higher
      2A-3 (LPL) - Body ground Always 10 kΩ or higher
      Fig 6: Identifying H5 And H9 Headlight Bulb Connector Terminals
      G05273787Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to Next step 

  7. CHECK HARNESS AND CONNECTOR (BULB - BODY GROUND) 
    1. Measure the resistance according to the value(s) in the table below.

      Resistance 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester connection Condition Specified value
      H5-1 (Headlight LH) - Body ground Always Below 1 Ω
      H9-1 (Headlight RH) - Body ground Always Below 1 Ω
      Fig 7: Identifying H5 And H9 Headlight Bulb Connector Terminals
      G05273788Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN  PROBLEM SYMPTOMS TABLE  

  8. CHECK HARNESS AND CONNECTOR (J/B NO. 2 - INSTRUMENT PANEL J/B) 
    1. Disconnect the connectors from the J/B No. 2 (power distributor) and instrument panel J/B.
    2. Measure the resistance according to the value(s) in the table below.

      Resistance 

      TESTER CONNECTION SPECIFIED CONDITION

      Tester connection Condition Specified value
      2H-8 (HRLY) - 1D-3 Always Below 1 Ω
      2H-8 (HRLY) - Body ground Always 10 kΩ or higher
      Fig 8: Identifying J/B No. 2 (Power Distributor) Connector Terminals
      G05273789Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      Fig 9: Identifying Instrument Panel Junction Block Assembly Front Side Connector Terminals
      G05273790Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN  PROBLEM SYMPTOMS TABLE  

  9. CHECK HARNESS AND CONNECTOR (SHORT CIRCUIT DRIVEN SIDE BY RELAY) 
    1. Preparation
      1. For easier disconnection remove the J/B No.2 and then take apart the connectors.
      2. Disconnect only the connector "2A".
    2. Check voltage
      1. Measure the voltage between the Mode Monitor Terminal and body ground.

        Result 

        RESULT REFERENCE CHART

        Condition Proceed to
        6.3 +- 2 V A
        Approx. 1 V B
        Fig 10: Identifying 2A Connector
        G05273791Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    B: REPLACE JUNCTION BLOCK NO.2 

    A: REPAIR OR REPLACE HARNESS OR CONNECTOR (SHORT CIRCUIT BETWEEN HEADLIGHT LO AND J/B NO.2) 

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