LIGHTING SYSTEM Headlight (HI-BEAM) Circuit

DESCRIPTION

The main body ECU receives light control switch and dimmer switch information signals from the headlight dimmer switch, and illuminates the high beam headlight.

WIRING DIAGRAM

A003EGXE04

INSPECTION PROCEDURE

Tech Tips

Inspect the fuses and bulbs for circuits related to this system before performing the following inspection procedure.

PROCEDURE


  1. PERFORM ACTIVE TEST USING INTELLIGENT TESTER (HEADLIGHT [HIGH])


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the intelligent tester on.

    4. Enter the following menus: Body / Main Body / Active Test / Head Light Hi.

    5. Check that the headlight (high) turns on/off.

      Main Body
      Tester Display Test Part Control Range Diagnostic Note
      Head Light Hi Headlight (High) ON or OFF -
      OK
      Headlight (high) turns on/off.

    NG

    CHECK HARNESS AND CONNECTOR (HEADLIGHT [HIGH] BULB - HEADLIGHT DIMMER RELAY) Click here

    OK

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

  2. CHECK HARNESS AND CONNECTOR (HEADLIGHT [HIGH] BULB - HEADLIGHT DIMMER RELAY)

    A003BYLE01
    Text in Illustration
    *1

    Front view of wire harness connector

    (to Headlight [High] Bulb [w/ AFS])
    *2 for LH
    *3 for RH
    *4

    Front view of wire harness connector

    (to Headlight [High] Bulb [w/o AFS])

    1. w/ AFS:


      1. Disconnect the headlight (high) A28 or A27 connector.

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

        Standard Voltage
        for LH
        Tester Connection Switch Condition Specified Condition
        A28-2 (HI) - Body ground Light control switch HEAD, dimmer switch high 11 to 14 V
        Light control switch HEAD, dimmer switch not high Below 1 V
        A28-5 (B) - Body ground Light control switch HEAD, dimmer switch high 11 to 14 V
        Light control switch HEAD, dimmer switch not high Below 1 V
        for RH
        Tester Connection Switch Condition Specified Condition
        A27-2 (HI) - Body ground Light control switch HEAD, dimmer switch high 11 to 14 V
        Light control switch HEAD, dimmer switch not high Below 1 V
        A27-5 (B) - Body ground Light control switch HEAD, dimmer switch high 11 to 14 V
        Light control switch HEAD, dimmer switch not high Below 1 V

    2. w/o AFS:


      1. Disconnect the headlight (high) A31 or A30 connector.

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

        Standard Voltage
        for LH
        Tester Connection Switch Condition Specified Condition
        A31-4 (HI) - Body ground Light control switch HEAD, dimmer switch high 11 to 14 V
        Light control switch HEAD, dimmer switch not high Below 1 V
        for RH
        Tester Connection Switch Condition Specified Condition
        A30-4 (HI) - Body ground Light control switch HEAD, dimmer switch high 11 to 14 V
        Light control switch HEAD, dimmer switch not high Below 1 V

    NG

    INSPECT HEADLIGHT DIMMER RELAY (DIMMER) Click here

    OK

  3. CHECK HARNESS AND CONNECTOR (HEADLIGHT [HIGH] BULB - BODY GROUND)

    A003BYLE02
    Text in Illustration
    *1

    Front view of wire harness connector

    (to Headlight [High] Bulb [w/ AFS])
    *2 for LH
    *3 for RH
    *4

    Front view of wire harness connector

    (to Headlight [High] Bulb [w/o AFS])

    1. w/ AFS:


      1. Disconnect the headlight (high) A28 or A27 connector.

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

        Standard Resistance
        for LH
        Tester Connection Condition Specified Condition
        A28-1 (E) - Body ground Always Below 1 Ω
        for RH
        Tester Connection Condition Specified Condition
        A27-1 (E) - Body ground Always Below 1 Ω

    2. w/o AFS:


      1. Disconnect the headlight (high) A31 or A30 connector.

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

        Standard Resistance
        for LH
        Tester Connection Condition Specified Condition
        A31-3 (E) - Body ground Always Below 1 Ω
        for RH
        Tester Connection Condition Specified Condition
        A30-3 (E) - Body ground Always Below 1 Ω
      Result
      Result Proceed to
      OK (w/ AFS) A
      OK (w/o AFS) B
      NG C

    B

    REPLACE HEADLIGHT ASSEMBLY Click here

    C

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    A

    REPLACE HEADLIGHT ASSEMBLY Click here

  4. INSPECT HEADLIGHT DIMMER RELAY (DIMMER)

    A003AL0E13

    1. Remove the headlight dimmer relay from the engine room No. 1 relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 Battery voltage not applied to terminals 1 and 2 10 kΩ or higher
      Battery voltage applied to terminals 1 and 2 Below 1 Ω

    NG

    REPLACE HEADLIGHT DIMMER RELAY

    OK

  5. CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER RELAY - BATTERY)

    A003BUZE01
    Text in Illustration
    *1

    Component without relay connected

    (Engine Room No. 1 Relay Block)
    *2 Headlight Dimmer Relay (DIMMER)

    1. Remove the headlight dimmer relay from the engine room No. 1 relay block.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      Headlight dimmer relay terminal 1 - Body ground Light control switch HEAD, dimmer switch low 11 to 14 V
      Headlight dimmer relay terminal 5 - Body ground Light control switch HEAD, dimmer switch low 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER RELAY - HEADLIGHT [HIGH] BULB)


    1. A003DBQE01
      Text in Illustration
      *1

      Component without relay connected

      (Engine Room No. 1 Relay Block)
      *2

      Front view of wire harness connector

      (to Headlight [High] Bulb [w/o AFS])
      *3 for LH
      *4 for RH
      *5

      Front view of wire harness connector

      (to Headlight [High] Bulb [w/ AFS])

      Remove the headlight dimmer relay from the engine room No. 1 relay block.

    2. w/ AFS:


      1. Disconnect the headlight (high) A28 or A27 connector.

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

        Standard Resistance
        for LH
        Tester Connection Condition Specified Condition
        Headlight dimmer relay terminal 3 - A28-2 (HI) Always Below 1 Ω
        Headlight dimmer relay terminal 3 - A28-5 (B) Always Below 1 Ω
        Headlight dimmer relay terminal 3 - Body ground Always 10 kΩ or higher
        for RH
        Tester Connection Condition Specified Condition
        Headlight dimmer relay terminal 3 - A27-2 (HI) Always Below 1 Ω
        Headlight dimmer relay terminal 3 - A27-5 (B) Always Below 1 Ω
        Headlight dimmer relay terminal 3 - Body ground Always 10 kΩ or higher

    3. w/o AFS:


      1. Disconnect the headlight (high) A31 or A30 connector.

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

        Standard Resistance
        for LH
        Tester Connection Condition Specified Condition
        Headlight dimmer relay terminal 3 - A31-4 (HI) Always Below 1 Ω
        Headlight dimmer relay terminal 3 - Body ground Always 10 kΩ or higher
        for RH
        Tester Connection Condition Specified Condition
        Headlight dimmer relay terminal 3 - A30-4 (HI) Always Below 1 Ω
        Headlight dimmer relay terminal 3 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER RELAY - MAIN BODY ECU)

    A003CQ1E01
    Text in Illustration
    *1

    Front view of wire harness connector

    (to Main Body ECU)

    1. Disconnect the D80 main body ECU connector.

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      D80-12 (DIM) - Body ground Light control switch HEAD 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE MAIN BODY ECU