Lighting System Light Control Switch Circuit

Body Electrical. Lexus Is250, Is220D. Gse20 Ale20
Lighting. Lexus Is250, Is220D. Gse20 Ale20

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE OF INTELLIGENT TESTER

INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY

CHECK HARNESS AND CONNECTOR

LIGHTING SYSTEM - Light Control Switch Circuit


DESCRIPTION

The combination switch ECU (windshield wiper switch assembly) receives the following switch information:
  1. Light control switch position is Off, Tail, Head, or Auto
  2. Headlight dimmer switch position is High, Low, or Flash (Pass)
  3. Turn signal switch position is LH, RH, or Off
  4. Fog light switch position is On or Off
The combination switch ECU then converts these signals to BEAN signals and sends them to each ECU via the multiplex communication system.
The headlight dimmer switch assembly includes the light control, headlight dimmer, turn signal, and fog light switches.

WIRING DIAGRAM


Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Light Control Switch Circuit


Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Light Control Switch Circuit


INSPECTION PROCEDURE

HINT:
Before starting the procedure, check that the multiplex communication system DTCs are not output (Click here).
1.READ VALUE OF INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG).

  1. Turn the intelligent tester on.

  1. Select the item(s) below in the DATA LIST, and read the display on the intelligent tester.

    DATA LIST: Combination Switch (Combination Switch ECU)
    Item
    		Measurement Item / Display
    (Range)
    		Normal Condition
    		Diagnostic Note
    Rear Fog Light Switch
    		Rear fog light switch signal / ON or OFF
    		ON: Rear fog light switch is in ON position
    OFF: Rear fog light switch is not in ON position
    		-
    Front Fog Light Switch
    		Front fog light switch signal / ON or OFF
    		ON: Front fog light switch is in ON position
    OFF: Front fog light switch is not in ON position
    		-
    Passing Light Switch
    		Passing light switch signal / ON or OFF
    		ON: Headlight dimmer switch is in FLASH (PASS) position
    OFF: Headlight dimmer switch is not in FLASH (PASS) position
    		-
    Dimmer HI Switch
    		High beam switch signal / ON or OFF
    		ON: Headlight dimmer switch is in HI position
    OFF: Headlight dimmer switch is not in HI position
    		-
    Light Auto Switch
    		Auto light switch signal / ON or OFF
    		ON: Light control switch is in AUTO position
    OFF: Light control switch is not in AUTO position
    		-
    Head Light Switch
    		Headlight control switch signal / ON or OFF
    		ON: Light control switch is in HEAD position
    OFF: Light control switch is not in HEAD position
    		-
    Tail Light Switch
    		Taillight switch signal / ON or OFF
    		ON: Light control switch is in TAIL or HEAD position
    OFF: Light control switch is off
    		-
    Turn Left Switch
    		Turn signal switch LH signal / ON or OFF
    		ON: Light control switch is in LH position
    OFF: Light control switch is not in LH position
    		-
    Turn Right Switch
    		Turn signal switch RH signal / ON or OFF
    		ON: Light control switch is in RH position
    OFF: Light control switch is not in RH position
    		-
    Ignition Switch Signal
    		Engine switch signal / ON or OFF
    		ON: Engine switch on (IG)
    OFF: Engine switch off
    		-
    OK:
    Condition information can be displayed.


NG
Go to step 2
OK

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

2.INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY
HINT:
Inspect the items that did not change as a result of monitoring the DATA LIST.


    Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Light Control Switch Circuit

  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 (LHD, RHD light control switch LH side type):
    Tester Connection
    		Switch Condition
    		Specified Condition
    f1-12 (EL) - f1-18 (T)
    		OFF
    		10 kΩ or higher
    f1-18 (T) - f1-19 (AUTO)
    		OFF
    		10 kΩ or higher
    f1-19 (AUTO) - f1-20 (H)
    		OFF
    		10 kΩ or higher
    f1-12 (EL) - f1-18 (T)
    		TAIL
    		Below 1 Ω
    f1-12 (EL) - f1-18 (T)
    		HEAD
    		Below 1 Ω
    f1-18 (T) - f1-20 (H)
    		HEAD
    		Below 1 Ω
    f1-12 (EL) - f1-19 (AUTO)
    		AUTO
    		Below 1 Ω
    Light Control Switch (RHD light control switch RH side type):
    Tester Connection
    		Switch Condition
    		Specified Condition
    f1-19 (EL) - f1-13 (T)
    		OFF
    		10 kΩ or higher
    f1-13 (T) - f1-12 (AUTO)
    		OFF
    		10 kΩ or higher
    f1-12 (AUTO) - f1-11 (H)
    		OFF
    		10 kΩ or higher
    f1-19 (EL) - f1-13 (T)
    		TAIL
    		Below 1 Ω
    f1-19 (EL) - f1-13 (T)
    		HEAD
    		Below 1 Ω
    f1-13 (T) - f1-11 (H)
    		HEAD
    		Below 1 Ω
    f1-19 (EL) - f1-12 (AUTO)
    		AUTO
    		Below 1 Ω
    Headlight Dimmer Switch (LHD, RHD light control switch LH side type):
    Tester Connection
    		Switch Condition
    		Specified Condition
    f1-11 (HU) - f1-12 (EL)
    		LOW BEAM
    		Below 1 Ω
    f1-11 (HU) - f1-12 (EL)
    		HI BEAM
    		Below 1 Ω
    f1-12 (EL) - f1-17 (HF)
    		HI BEAM
    		Below 1 Ω
    Headlight Dimmer Switch (RHD light control switch RH side type):
    Tester Connection
    		Switch Condition
    		Specified Condition
    f1-15 (HU) - f1-19 (EL)
    		LOW BEAM
    		Below 1 Ω
    f1-15 (HU) - f1-19 (EL)
    		HI BEAM
    		Below 1 Ω
    f1-19 (EL) - f1-14 (HF)
    		HI BEAM
    		Below 1 Ω
    Turn Signal Switch (LHD, RHD light control switch LH side type):
    Tester Connection
    		Switch Condition
    		Specified Condition
    f1-12 (EL) - f1-13 (TR)
    		Right turn
    		Below 1 Ω
    f1-12 (EL) - f1-13 (TR)
    		Neutral
    		10 kΩ or higher
    f1-12 (EL) - f1-15 (TL)
    		Neutral
    		10 kΩ or higher
    f1-12 (EL) - f1-15 (TL)
    		Left turn
    		Below 1 Ω
    Turn Signal Switch (RHD light control switch RH side type):
    Tester Connection
    		Switch Condition
    		Specified Condition
    f1-19 (EL) - f1-16 (TR)
    		Right turn
    		Below 1 Ω
    f1-19 (EL) - f1-16 (TR)
    		Neutral
    		10 kΩ or higher
    f1-19 (EL) - f1-18 (TL)
    		Neutral
    		10 kΩ or higher
    f1-19 (EL) - f1-18 (TL)
    		Left turn
    		Below 1 Ω
    Fog Light Switch (LHD, RHD light control switch LH side type):
    Tester Connection
    		Switch Condition
    		Specified Condition
    f1-3 (LFG) - f1-4 (BFG)
    		OFF
    		10 kΩ or higher
    f1-4 (BFG) - f1-2 (B)
    		OFF
    		10 kΩ or higher
    f1-3 (LFG) - f1-2 (B)
    		OFF
    		10 kΩ or higher
    f1-3 (LFG) - f1-4 (BFG)
    		Front fog light switch ON
    		Below 1 Ω
    f1-3 (LFG) - f1-4 (BFG)
    		Rear fog light switch ON
    		Below 1 Ω
    f1-4 (BFG) - f1-2 (B)
    		Rear fog light switch ON
    		Below 1 Ω
    f1-3 (LFG) - f1-2 (B)
    		Rear fog light switch ON
    		Below 1 Ω
    Fog Light Switch (RHD light control switch RH side type):
    Tester Connection
    		Switch Condition
    		Specified Condition
    f1-8 (LFG) - f1-7 (BFG)
    		OFF
    		10 kΩ or higher
    f1-7 (BFG) - f1-9 (RFG)
    		OFF
    		10 kΩ or higher
    f1-8 (LFG) - f1-9 (RFG)
    		OFF
    		10 kΩ or higher
    f1-8 (LFG) - f1-7 (BFG)
    		Front fog light switch ON
    		Below 1 Ω
    f1-8 (LFG) - f1-7 (BFG)
    		Rear fog light switch ON
    		Below 1 Ω
    f1-7 (BFG) - f1-9 (RFG)
    		Rear fog light switch ON
    		Below 1 Ω
    f1-8 (LFG) - f1-9 (RFG)
    		Rear fog light switch ON
    		Below 1 Ω


NG
REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY
OK


3.CHECK HARNESS AND CONNECTOR


    Lexus Is250, Is220D. Gse20 Ale20.Lighting.Lighting System.Lighting System Light Control Switch Circuit

  1. Disconnect the J26 windshield wiper switch assembly connector.

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

    Standard resistance:
    Tester Connection
    		Condition
    		Specified Condition
    J26-5 (E) - Body ground
    		Always
    		Below 1 Ω

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

    Standard voltage:
    Tester Connection
    		Condition
    		Specified Condition
    J26-1 (B) - J26-5 (E)
    		Always
    		10 to 14 V
    J26-2 (IG) - J26-5 (E)
    		Engine switch on (IG)
    		10 to 14 V


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE WINDSHIELD WIPER SWITCH ASSEMBLY