LIGHTING SYSTEM Light Control Switch Circuit

DESCRIPTION

The main body ECU receives the following signals:


Tech Tips

When performing troubleshooting, inspect the switch that is related to the malfunction. For example, if both right and left low beam headlights do not illuminate, read the light control switch HEAD signal value only in the data list. If the value is normal, perform the headlight relay active test.

WIRING DIAGRAM

A017FRWE16

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch on (IG).

    3. Turn the intelligent tester on.

    4. Select the following menu items: Body Electrical / Main Body / Data List.

    5. Read the displays on the intelligent tester.

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

      ON: Dimmer switch in HIGH

      OFF: Dimmer switch in LOW

      		 -
      Passing Light SW Dimmer switch FLASH signal / ON or OFF

      ON: Dimmer switch in HIGH FLASH (PASS)

      OFF: Dimmer switch not in HIGH FLASH (PASS)

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

      ON: Front fog light switch ON

      OFF: Front fog light switch OFF

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

      ON: Rear fog light switch ON

      OFF: Rear fog light switch OFF

      		 -
      Light Auto SW Light control switch AUTO signal / ON or OFF

      ON: Light control switch in AUTO

      OFF: Light control switch not in AUTO

      		 -
      Headlight SW Light control switch HEAD signal / ON or OFF

      ON: Light control switch in HEAD

      OFF: Light control switch not in HEAD

      		 -
      Taillight SW Light control switch TAIL signal / ON or OFF

      ON: Light control switch in TAIL or HEAD

      OFF: Light control switch in neither TAIL nor HEAD

      		 -
      OK
      Normal conditions listed above are displayed.

    NG

    INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY Click here

    OK

    PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE Click here

  2. INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY


    1. Inspect the headlight dimmer switch assembly Click here.

      OK
      Headlight dimmer switch assembly is normal.

    NG

    REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY

    OK

  3. CHECK HARNESS AND CONNECTOR (SWITCH - INSTRUMENT PANEL J/B AND BODY GROUND)


    1. for LHD:


      1. Disconnect the D12 headlight dimmer switch assembly connector.

        A017F1DE05

      2. Disconnect the D6 and D7 main body ECU connectors.

      3. Disconnect the 1N instrument panel junction block connector.

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

        Standard resistance
        Tester Connection Condition Specified Condition
        D12-2 (B) - D6-9 (RFOG) Always Below 1 Ω
        D12-4 (BFG) - D6-28 (FFOG) Always Below 1 Ω
        D12-11 (HU) - 1N-2 (HU) Always Below 1 Ω
        D12-17 (HF) - D7-13 (HF) Always Below 1 Ω
        D12-18 (T) - D7-23 (TAIL) Always Below 1 Ω
        D12-19 (A) - D7-21 (A) Always Below 1 Ω
        D12-20 (H) - D6-17 (HEAD) Always Below 1 Ω
        D12-2 (B) - Body ground Always 10 kΩ or higher
        D12-3 (LFG) - Body ground Always 10 kΩ or higher
        D12-4 (BFG) - Body ground Always 10 kΩ or higher
        D12-11 (HU) - Body ground Always 10 kΩ or higher
        D12-17 (HF) - Body ground Always 10 kΩ or higher
        D12-18 (T) - Body ground Always 10 kΩ or higher
        D12-19 (A) - Body ground Always 10 kΩ or higher
        D12-20 (H) - Body ground Always 10 kΩ or higher
        D12-12 (EL) - Body ground Always Below 1 Ω
        D12-3 (LFG) - Body ground Always Below 1 Ω

    2. for RHD:


      1. Disconnect the D12 headlight dimmer switch assembly connector.

        A017F1DE04

      2. Disconnect the D6 and D7 main body ECU connectors.

      3. Disconnect the 1N instrument panel junction block connector.

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

        Standard resistance
        Tester Connection Condition Specified Condition
        D12-13 (T) - D7-23 (TAIL) Always Below 1 Ω
        D12-7 (BFG) - D6-28 (FFOG) Always Below 1 Ω
        D12-11 (H) - D6-17 (HEAD) Always Below 1 Ω
        D12-12 (A) - D7-21 (A) Always Below 1 Ω
        D12-14 (HF) - D7-13 (HF) Always Below 1 Ω
        D12-20 (HU) - 1N-2 (HU) Always Below 1 Ω
        D12-13 (T) - Body ground Always 10 kΩ or higher
        D12-7 (BFG) - Body ground Always 10 kΩ or higher
        D12-11 (H) - Body ground Always 10 kΩ or higher
        D12-12 (A) - Body ground Always 10 kΩ or higher
        D12-14 (HF) - Body ground Always 10 kΩ or higher
        D12-20 (HU) - Body ground Always 10 kΩ or higher
        D12-19 (EL) - Body ground Always Below 1 Ω
        D12-8 (LFG) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK)