LIGHTING SYSTEM > Headlight Dimmer Switch Circuit

for Preparation Click here


DESCRIPTION

The main body ECU (multiplex network body ECU) receives the following switch information:
  1. Light control switch position is off, tail, head or AUTO
  2. Dimmer switch position is high, low or high flash (pass)
  3. Front fog light switch position is on or off

WIRING DIAGRAM


for LHD, RHD Light Control Switch LH Side Type:

E224483E01


for RHD Light Control Switch RH Side Type:

E224483E03


INSPECTION PROCEDURE

1.READ VALUE USING INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the intelligent tester on.

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

  1. Read the display on the intelligent tester.

    Main Body 
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Dimmer SW
    		Dimmer switch high position signal/ON or OFF
    		ON: Dimmer switch in high or high flash
    OFF: Dimmer switch in low position
    		-
    Passing Light SW
    		Dimmer switch high flash position (pass) signal/ON or OFF
    		ON: Dimmer switch in high flash position
    OFF: Dimmer switch not in high flash position
    		-
    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 position signal/ON or OFF
    		ON: Light control switch in AUTO position
    OFF: Light control switch not in AUTO position
    		-
    Head Light SW (Head)
    		Light control switch head position signal/ON or OFF
    		ON: Light control switch in head position
    OFF: Light control switch not in head position
    		-
    Head Light SW (Tail)
    		Light control switch tail position signal/ON or OFF
    		ON: Light control switch in tail or head position
    OFF: Light control switch in neither tail nor head position
    		-

    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

HINT:
Inspect the items that did not change as a result of monitoring the Data List.



    E223779E03

  1. Remove the headlight dimmer switch assembly (Click here).

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

    Standard Resistance:
    Light Control Switch 
    Tester Connection
    		Switch Condition
    		Specified Condition
    12 (EL) - 18 (T)
    		Light control switch off
    		10 kΩ or higher
    18 (T) - 19 (A)
    		Light control switch off
    		10 kΩ or higher
    19 (A) - 20 (H)
    		Light control switch off
    		10 kΩ or higher
    12 (EL) - 18 (T)
    		Light control switch in tail position
    		Below 1 Ω
    12 (EL) - 18 (T)
    		Light control switch in head position
    		Below 1 Ω
    18 (T) - 20 (H)
    		Light control switch in head position
    		Below 1 Ω
    12 (EL) - 19 (A)
    		Light control switch in AUTO position
    		Below 1 Ω
    Dimmer Switch 
    Tester Connection
    		Switch Condition
    		Specified Condition
    11 (HU) - 12 (EL)
    		Dimmer switch in low position
    		10 kΩ or higher
    11 (HU) - 12 (EL)
    		Dimmer switch in high position
    		Below 1 Ω
    12 (EL) - 17 (HF)
    		Dimmer switch in high flash position
    		Below 1 Ω
    Front Fog Light Switch 
    Tester Connection
    		Switch Condition
    		Specified Condition
    3 (LFG) - 4 (BFG)
    		Fog light switch off
    		10 kΩ or higher
    3 (LFG) - 4 (BFG)
    		Fog light switch on
    		Below 1 Ω
    Rear Fog Light Switch 
    Tester Connection
    		Switch Condition
    		Specified Condition
    3 (LFG) - 2 (B)
    		Fog light switch off
    		10 kΩ or higher
    3 (LFG) - 2 (B)
    		Fog light switch on
    		Below 1 Ω

    OK:
    Headlight dimmer switch assembly is normal.

    Text in Illustration 
    *a
    		Component without harness connected
    (Headlight Dimmer Switch Assembly for LHD, RHD Light Control Switch LH Side Type)



    E223779E04

  1. Remove the headlight dimmer switch assembly (Click here).

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

    Standard Resistance:
    Light Control Switch 
    Tester Connection
    		Switch Condition
    		Specified Condition
    19 (EL) - 13 (T)
    		Light control switch off
    		10 kΩ or higher
    13 (T) - 12 (A)
    		Light control switch off
    		10 kΩ or higher
    12 (A) - 11 (H)
    		Light control switch off
    		10 kΩ or higher
    19 (EL) - 13 (T)
    		Light control switch in tail position
    		Below 1 Ω
    19 (EL) - 13 (T)
    		Light control switch in head position
    		Below 1 Ω
    13 (T) - 11 (H)
    		Light control switch in head position
    		Below 1 Ω
    19 (EL) - 12 (A)
    		Light control switch in AUTO position
    		Below 1 Ω
    Dimmer Switch 
    Tester Connection
    		Switch Condition
    		Specified Condition
    20 (HU) - 19 (EL)
    		Dimmer switch in low position
    		10 kΩ or higher
    20 (HU) - 19 (EL)
    		Dimmer switch in high position
    		Below 1 Ω
    19 (EL) - 14 (HF)
    		Dimmer switch in high flash position
    		Below 1 Ω
    Front Fog Light Switch 
    Tester Connection
    		Switch Condition
    		Specified Condition
    8 (LFG) - 7 (BFG)
    		Fog light switch off
    		10 kΩ or higher
    8 (LFG) - 7 (BFG)
    		Fog light switch on
    		Below 1 Ω
    Rear Fog Light Switch 
    Tester Connection
    		Switch Condition
    		Specified Condition
    8 (LFG) - 9 (B)
    		Fog light switch off
    		10 kΩ or higher
    8 (LFG) - 9 (B)
    		Fog light switch on
    		Below 1 Ω

    OK:
    Headlight dimmer switch assembly is normal.

    Text in Illustration 
    *a
    		Component without harness connected
    (Headlight Dimmer Switch Assembly for RHD Light Control Switch RH Side Type)



NG
REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY (Click here)
OK


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

  1. Disconnect the H26 headlight dimmer switch assembly connector.

  1. Disconnect the H16 main body ECU (multiplex network body ECU) connector.

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

    Standard Resistance:
    for LHD, RHD Light Control Switch LH Side Type:
    Tester Connection
    		Condition
    		Specified Condition
    H26-4 (BFG) - H16-27 (FFOG)
    		Always
    		Below 1 Ω
    H26-11 (HU) - H16-5 (HU)
    		Always
    		Below 1 Ω
    H26-17 (HF) - H16-8 (HF)
    		Always
    		Below 1 Ω
    H26-18 (T) - H16-30 (TAIL)
    		Always
    		Below 1 Ω
    H26-19 (A) - H16-28 (A)
    		Always
    		Below 1 Ω
    H26-20 (H) - H16-29 (HEAD)
    		Always
    		Below 1 Ω
    H26-2 (B) - H16-1 (RFOG)
    		Always
    		Below 1 Ω
    H26-4 (BFG) - Body ground
    		Always
    		10 kΩ or higher
    H26-11 (HU) - Body ground
    		Always
    		10 kΩ or higher
    H26-17 (HF) - Body ground
    		Always
    		10 kΩ or higher
    H26-18 (T) - Body ground
    		Always
    		10 kΩ or higher
    H26-19 (A) - Body ground
    		Always
    		10 kΩ or higher
    H26-20 (H) - Body ground
    		Always
    		10 kΩ or higher
    H26-12 (EL) - Body ground
    		Always
    		Below 1 Ω
    H26-3 (LFG) - Body ground
    		Always
    		Below 1 Ω
    H26-2 (B) - Body ground
    		Always
    		Below 1 Ω
    for RHD Light Control Switch RH Side Type:
    Tester Connection
    		Condition
    		Specified Condition
    H26-7 (BFG) - H16-27 (FFOG)
    		Always
    		Below 1 Ω
    H26-20 (HU) - H16-5 (HU)
    		Always
    		Below 1 Ω
    H26-14 (HF) - H16-8 (HF)
    		Always
    		Below 1 Ω
    H26-13 (T) - H16-30 (TAIL)
    		Always
    		Below 1 Ω
    H26-12 (A) - H16-28 (A)
    		Always
    		Below 1 Ω
    H26-11 (H) - H16-29 (HEAD)
    		Always
    		Below 1 Ω
    H26-9 (B) - H16-1 (RFOG)
    		Always
    		Below 1 Ω
    H26-7 (BFG) - Body ground
    		Always
    		10 kΩ or higher
    H26-20 (HU) - Body ground
    		Always
    		10 kΩ or higher
    H26-14 (HF) - Body ground
    		Always
    		10 kΩ or higher
    H26-13 (T) - Body ground
    		Always
    		10 kΩ or higher
    H26-12 (A) - Body ground
    		Always
    		10 kΩ or higher
    H26-11 (H) - Body ground
    		Always
    		10 kΩ or higher
    H26-19 (EL) - Body ground
    		Always
    		Below 1 Ω
    H26-8 (LFG) - Body ground
    		Always
    		Below 1 Ω
    H26-9 (B) - Body ground
    		Always
    		Below 1 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) (Click here)