LIGHTING SYSTEM Light Control Switch Circuit

DESCRIPTION

The main body ECU receives the following signals:


Tech Tips


  • This circuit is only for vehicles with automatic light control or daytime running light control.

  • If the vehicle has automatic light control or daytime running light control, the exterior lights (headlights, taillights, front fog lights* and rear fog light) are controlled by the main body ECU.

  • If the vehicle does not have automatic light control or daytime running light control, the exterior lights (headlights, taillights, front fog lights* and rear fog light) are not controlled by the main body ECU. Perform troubleshooting according to the Problem Symptoms Table Click here.

  • When performing troubleshooting, inspect the switch that is related to the malfunction. For example, if both the right and left low beam headlights do not illuminate, read the light control switch head signal value in the Data List. If the value is normal, perform the headlight relay Active Test.


WIRING DIAGRAM

A01IOYQE01

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (HEADLIGHT DIMMER SWITCH ASSEMBLY)


    1. Using the intelligent tester, read the Data List Click here.

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

      ON: Dimmer switch in high or high flash

      OFF: Dimmer switch in low

      		 -
      Passing Light SW Dimmer switch high flash signal / ON or OFF

      ON: Dimmer switch in high flash

      OFF: Dimmer switch not in high flash

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

      ON: Rear fog light switch on

      OFF: Rear fog light switch off

      		 -
      Front Fog Light SW*1 Front fog light switch signal / ON or OFF

      ON: Front fog light switch on

      OFF: Front fog light switch off

      		 -
      Auto Light SW*2 Light control switch AUTO signal / ON or OFF

      ON: Light control switch in AUTO

      OFF: Light control switch not in AUTO

      		 -
      Head Light SW (Head) Light control switch head signal / ON or OFF

      ON: Light control switch in head

      OFF: Light control switch not in head

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

      ON: Light control switch in tail or head

      OFF: Light control switch not in tail or head

      		 -

      • *1: w/ Front Fog Light

      • *2: w/ Automatic Light Control System

      OK
      The display is as specified in the normal condition column.

    NG

    INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY Click here

    OK

    PROCEED TO NEXT SUSPECTED AREA 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 Click here

    OK

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

    A01IPMRE13

    1. Disconnect the H13 headlight dimmer switch assembly connector.

    2. Disconnect the H79 and H81 main body ECU connectors.

    3. Disconnect the DJ instrument panel junction block assembly connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      H13-2 (B) - H81-9 (RFOG) Always Below 1 Ω
      H13-4 (BFG) - H81-13 (FFOG)*1 Always Below 1 Ω
      H13-11 (HU) - DJ-4 (HU) Always Below 1 Ω
      H13-17 (HF) - H79-22 (HF) Always Below 1 Ω
      H13-18 (T) - H79-21 (TAIL) Always Below 1 Ω
      H13-19 (A) - H81-18 (A)*2 Always Below 1 Ω
      H13-20 (H) - H81-12 (HEAD) Always Below 1 Ω
      H13-2 (B) - Body ground Always 10 kΩ or higher
      H13-4 (BFG) - Body ground Always 10 kΩ or higher
      H13-11 (HU) - Body ground Always 10 kΩ or higher
      H13-17 (HF) - Body ground Always 10 kΩ or higher
      H13-18 (T) - Body ground Always 10 kΩ or higher
      H13-19 (A) - Body ground*2 Always 10 kΩ or higher
      H13-20 (H) - Body ground Always 10 kΩ or higher
      H13-12 (E) - Body ground Always Below 1 Ω
      H13-3 (LFG) - Body ground Always Below 1 Ω

      • *1: w/ Front Fog Light

      • *2: w/ Automatic Light Control System

      Text in Illustration
      *1

      Front view of wire harness connector

      (to Main Body ECU)

      		 *2 w/ Front Fog Light
      *3 w/ Automatic Light Control System *4

      Front view of wire harness connector

      (to Instrument Panel Junction Block Assembly)
      *5

      Front view of wire harness connector

      (to Headlight Dimmer Switch Assembly)

      		 - -

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE MAIN BODY ECU (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)