LIGHTING SYSTEM Headlight Dimmer Switch Circuit

DESCRIPTION

The main body ECU (instrument panel junction block assembly) receives light control switch signals, dimmer switch signal, fog light switch (front/rear) signals from the headlight dimmer switch assembly.

WIRING DIAGRAM

A005763E03

CAUTION / NOTICE / HINT

Note


  • As the door control battery is installed between the vehicle battery and main body ECU (instrument panel junction block assembly), first perform the inspections in On-Vehicle Inspection to confirm that there are no malfunctions in the power source circuit for the main body ECU (instrument panel junction block assembly) before performing this troubleshooting procedure.

PROCEDURE


  1. READ VALUE USING GTS (HEADLIGHT DIMMER SWITCH)


    1. Using the GTS, read the Data List Click here.

      Main Body
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Dimmer SW Dimmer switch signal / ON or OFF

      ON: Dimmer switch on

      OFF: Dimmer switch off

      		 -
      Passing Light SW Passing light switch signal / ON or OFF

      ON: Passing light switch on

      OFF: Passing light switch off

      		 -
      Front Fog Light SW Front fog light switch signal / ON or OFF

      ON: Front fog light switch on

      OFF: Front fog light switch off

      		 w/ Front Fog Light
      Rear Fog Light SW Rear fog light switch signal / ON or OFF

      ON: Rear fog light switch on

      OFF: Rear fog light switch off

      		 w/ Rear Fog Light
      Auto Light SW Auto light switch signal / ON or OFF

      ON: Auto light switch on

      OFF: Auto light switch off

      		 w/ Automatic Light Control System
      Head Light SW (Head) Headlight switch signal / ON or OFF

      ON: Headlight switch on

      OFF: Headlight switch off

      		 -
      Head Light SW (Tail) Taillight switch signal / ON or OFF

      ON: Taillight switch on

      OFF: Taillight switch off

      		 -

    OK

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

    NG

  2. INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY (TURN SIGNAL SWITCH)


    1. Remove the headlight dimmer switch assembly Click here.

    2. Inspect the headlight dimmer switch assembly Click here.


    NG

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

    OK

  3. CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER SWITCH ASSEMBLY - MAIN BODY ECU AND BODY GROUND)


    1. Disconnect the D7 headlight dimmer switch assembly connector.

    2. Disconnect the D79, D81 and DJ main body ECU (instrument panel junction block assembly) connectors.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D7-18 (T) - D79-21 (TAIL) Always Below 1 Ω
      D7-20 (H) - D81-12 (HEAD) Always Below 1 Ω
      D7-19 (A) - D81-16 (A) Always Below 1 Ω
      D7-11 (HU) - DJ-4 (HU) Always Below 1 Ω
      D7-17 (HF) - D79-22 (HF) Always Below 1 Ω
      D7-4 (BFG) - D81-13 (FFOG) Always Below 1 Ω
      D7-2 (B) - D79-9 (RFOG) Always Below 1 Ω
      D7-18 (T) - Body ground Always 10 kΩ or higher
      D7-20 (H) - Body ground Always 10 kΩ or higher
      D7-19 (A) - Body ground Always 10 kΩ or higher
      D7-11 (HU) - Body ground Always 10 kΩ or higher
      D7-17 (HF) - Body ground Always 10 kΩ or higher
      D7-4 (BFG) - Body ground Always 10 kΩ or higher
      D7-2 (B) - Body ground Always 10 kΩ or higher
      D7-3 (LFG) - Body ground Always Below 1 Ω

    OK

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR