LIGHTING SYSTEM Headlight Relay Circuit

DESCRIPTION

The main body ECU controls the headlight relay and headlight dimmer relay.

WIRING DIAGRAM

B004672E03

CAUTION / NOTICE / HINT

Note

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

PROCEDURE


  1. PERFORM ACTIVE TEST USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

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

    5. According to the display on the GTS, perform the Active Test.

      Main Body
      Tester Display Test Part Control Range Diagnostic Note
      Headlight Relay Headlight relay OFF or ON -
      Head Light Hi Headlight dimmer relay OFF or ON Light control switch is in HEAD position

    6. Check the illuminating condition of the low beam and high beam headlights.

      Result
      Result Proceed to
      Low beam headlights and high beam headlights are normal. A
      Low beam headlights and high beam headlights do not illuminate. B
      Low beam headlights do not illuminate (High beam headlights are normal). C
      High beam headlights do not illuminate (Low beam headlights are normal). D

    A

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

    C

    INSPECT HEADLIGHT DIMMER RELAY (DIM) Click here

    D

    INSPECT HEADLIGHT DIMMER RELAY (DIM) Click here

    B

  2. INSPECT HEADLIGHT RELAY (H-LP/US-DRL)


    1. Remove the headlight relay (H-LP/US-DRL) from No. 2 engine room relay block.

    2. Inspect the headlight relay (H-LP/US-DRL).

      Click here


    NG

    REPLACE HEADLIGHT RELAY (H-LP/US-DRL)

    OK

  3. INSPECT HEADLIGHT DIMMER RELAY (DIM)


    1. Remove the headlight dimmer relay (DIM) from No. 2 engine room relay block.

    2. Inspect the headlight dimmer relay (DIM) from No. 2 engine room relay block.

      Click here


    NG

    REPLACE HEADLIGHT DIMMER RELAY (DIM)

    OK

  4. CHECK HARNESS AND CONNECTOR (HEADLIGHT RELAY(H-LP/US-DRL) - BATTERY)


    1. B0045NDC02
      *1 No. 2 Engine Room Relay Block
      *2 Headlight Relay (H-LP/US-DRL) Holder

      Remove the headlight relay (H-LP/US-DRL) from the No. 2 engine room relay block.

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      H-LP/US-DRL relay terminal 1 - Body ground Always 11 to 14 V
      H-LP/US-DRL relay terminal 3 - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (HEADLIGHT RELAY (H-LP/US-DRL) - HEADLIGHT DIMMER RELAY (DIM))


    1. Remove the headlight relay (H-LP/US-DRL) from the No. 2 engine room relay block.

    2. Remove the headlight dimmer relay (DIM) from the No. 2 engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H-LP/US-DRL Relay terminal 5 - DIM relay terminal 1 Always Below 1 Ω
      H-LP/US-DRL Relay terminal 5 - DIM relay terminal 3 Always Below 1 Ω
      H-LP/US-DRL Relay terminal 5 or DIM Relay terminal 1 - Body ground Always 10 kΩ or higher
      H-LP/US-DRL Relay terminal 5 or DIM Relay terminal 3 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - HEADLIGHT RELAY (H-LP/US-DRL) AND HEADLIGHT DIMMER RELAY (DIM))


    1. Disconnect the 3C instrument panel junction block assembly connector.

    2. Remove the headlight relay (H-LP/US-DRL) from the No. 2 engine room relay block.

    3. Remove the headlight dimmer relay (DIM) from the No. 2 engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      3C-18 - H-LP/US-DRL Relay terminal 2 Always Below 1 Ω
      3C-35 - DIM Relay terminal 2 Always Below 1 Ω
      H-LP/US-DRL Relay terminal 2 or 3C-18 - Body ground Always 10 kΩ or higher
      DIM Relay terminal 2 or 3C-35 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  7. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


    1. Remove the instrument panel junction block assembly.

    2. Remove the main body ECU from the instrument panel junction block assembly.

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

      B00482VC01
      *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      3C-18 - MB-15 (HRLY) Always Below 1 Ω
      3C-35 - MB-22 (DIM) Always Below 1 Ω

    OK

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

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

  8. INSPECT HEADLIGHT DIMMER RELAY (DIM)


    1. Remove the headlight dimmer relay (DIM).

    2. Inspect the headlight dimmer relay (DIM).

      Click here

      Result
      Proceed to
      OK
      NG

    OK

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

    NG

    REPLACE HEADLIGHT DIMMER RELAY (DIM)

  9. INSPECT HEADLIGHT DIMMER RELAY (DIM)


    1. Remove the headlight dimmer relay (DIM).

    2. Inspect the headlight dimmer relay (DIM).

      Click here

      Result
      Proceed to
      OK
      NG

    NG

    REPLACE HEADLIGHT DIMMER RELAY (DIM)

    OK

  10. CHECK HARNESS AND CONNECTOR (HEADLIGHT RELAY (H-LP/US-DRL) - HEADLIGHT DIMMER RELAY (DIM))


    1. Remove the headlight relay (H-LP/US-DRL) from the No. 2 engine room relay block.

    2. Remove the headlight dimmer relay (DIM) from the No. 2 engine room relay block.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H-LP/US-DRL Relay terminal 5 - DIM Relay terminal 1 Always Below 1 Ω
      H-LP/US-DRL Relay terminal 5 or DIM Relay terminal 1 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  11. CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER RELAY (DIM) - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)


    1. Remove the headlight dimmer relay (DIM) from the No. 2 engine room relay block.

    2. Disconnect the 3C instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      DIM Relay terminal 2 - 3C-35 Always Below 1 Ω
      DIM terminal 2 or 3C-35 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  12. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


    1. Remove the instrument panel junction block assembly.

    2. Remove the main body ECU from the instrument panel junction block assembly.

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

      B00482DC01
      *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

      		 - -
      Standard Resistance
      Tester Connection Condition Specified Condition
      3C-35 - MB-22 (DIM) Always Below 1 Ω

    OK

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

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY