LIGHTING SYSTEM > Light Control Switch Circuit

for Preparation Click here


DESCRIPTION

  1. This circuit is only for vehicles with the daytime running light system or with automatic light control system.

    HINT:
    1. For vehicles with the daytime running light system or with automatic light control system, the main body ECU receives switch signals to control the exterior lights (headlights, taillights, front fog light and rear fog light).
    2. For vehicles without the daytime running light system and without automatic light control system, 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).

  2. The main body ECU receives the following signals:
    1. Light control switch TAIL, HEAD, or AUTO signal
    2. Dimmer switch HIGH or HIGH FLASH (PASS) signal
    3. Front fog light switch signal
    4. Rear fog light switch signal

      HINT:
      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


E177342E01


INSPECTION PROCEDURE

1.READ VALUE USING INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the tester on.

  1. Enter the following menus: Body / Main Body / Data List.

  1. According to the display on the tester, read the Data List.

    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
    		Front fog light switch signal
    ON or OFF
    		ON: Front fog light switch ON
    OFF: Front fog light switch OFF
    		-
    Auto Light SW
    		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 in neither TAIL nor HEAD
    		-

    OK:
    Normal conditions listed above are displayed.



NG
Go to step 2
OK

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

2.INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY


    E174463E01

  1. Remove the headlight dimmer switch assembly.

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

    Standard Resistance:
    Light Control Switch 
    Tester Connection
    		Switch Condition
    		Specified Condition
    18 (T) - 12 (E)
    18 (T) - 19 (A)
    19 (A) - 20 (H)
    		OFF
    		10 kΩ or higher
    18 (T) - 12 (E)
    		TAIL
    		Below 1 Ω
    18 (T) - 12 (E)
    		HEAD
    		Below 1 Ω
    18 (T) - 20 (H)
    		Below 1 Ω
    19 (A) - 12 (E)
    		AUTO
    		Below 1 Ω
    Dimmer Switch 
    Tester Connection
    		Switch Condition
    		Specified Condition
    17 (HF) - 12 (E)
    		HIGH FLASH
    		Below 1 Ω
    11 (HU) - 12 (E)
    		Below 1 Ω
    11 (HU) - 12 (E)
    		HIGH
    		Below 1 Ω
    Front Fog Light Switch 
    Tester Connection
    		Switch Condition
    		Specified Condition
    3 (LFG) - 4 (BFG)
    		OFF
    		10 kΩ or higher
    3 (LFG) - 4 (BFG)
    		ON
    		Below 1 Ω
    Rear Fog Light Switch 
    Tester Connection
    		Switch Condition
    		Specified Condition
    2 (B) - 3 (LFG)
    		OFF
    		10 kΩ or higher
    2 (B) - 3 (LFG)
    		ON
    		Below 1 Ω

Text in Illustration 
*1
Component without harness connected
(Headlight Dimmer Switch Assembly)

  1. Reinstall the headlight dimmer switch assembly.



NG
REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY (Click here)
OK


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


    E174464E01

  1. Disconnect the D24 headlight dimmer switch assembly connector.

  1. Disconnect the D42 main body ECU connectors.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    D24-2 (B) - D42-1 (RFOG)
    		Always
    		Below 1 Ω
    D24-2 (B) - Body ground
    		Always
    		10 kΩ or higher
    D24-4 (BFG) - D42-27 (FFOG)
    		Always
    		Below 1 Ω
    D24-4 (BFG) - Body ground
    		Always
    		10 kΩ or higher
    D24-11 (HU) - D42-5 (HU)
    		Always
    		Below 1 Ω
    D24-11 (HU) - Body ground
    		Always
    		10 kΩ or higher
    D24-17 (HF) - D42-8 (HF)
    		Always
    		Below 1 Ω
    D24-17 (HF) - Body ground
    		Always
    		10 kΩ or higher
    D24-18 (T) - D42-30 (TAIL)
    		Always
    		Below 1 Ω
    D24-18 (T) - Body ground
    		Always
    		10 kΩ or higher
    D24-19 (A) - D42-28 (A)
    		Always
    		Below 1 Ω
    D24-19 (A) - Body ground
    		Always
    		10 kΩ or higher
    D24-20 (H) - D42-29 (HEAD)
    		Always
    		Below 1 Ω
    D24-20 (H) - Body ground
    		Always
    		10 kΩ or higher
    D24-3 (LFG) - Body ground
    		Always
    		Below 1 Ω
    D24-12 (E) - Body ground
    		Always
    		Below 1 Ω

Text in Illustration 
*1
Front view of wire harness connector
(to Headlight Dimmer Switch Assembly)
*2
Front view of wire harness connector
(to Main Body ECU)

  1. Reconnect the headlight dimmer switch assembly connector.

  1. Reconnect the main body ECU connectors.



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE MAIN BODY ECU (Click here)