LIGHTING SYSTEM Headlight Dimmer Switch Circuit

DESCRIPTION

he main body ECU (multiplex network body ECU) receives light control switch signals, dimmer switch signals, fog light switch (front*1/rear*2) signals from the headlight dimmer switch.

• *1: w/ Front Fog Light

• *2: w/ Rear Fog Light

WIRING DIAGRAM

CAUTION / NOTICE / HINT

PROCEDURE

1. READ VALUE USING GTS (HEADLIGHT DIMMER SWITCH)

   
   

   1. Using the GTS, read the Data List.

      Click here

      
      Body Electrical > Main Body > Data List

      Tester Display	Measurement Item	Range	Normal Condition	Diagnostic Note
      Dimmer SW	Headlight dimmer switch high position signal	ON or OFF	ON: Headlight dimmer switch in high or high flash position OFF: Headlight dimmer switch in low position	-
      Passing Light SW	Headlight dimmer switch high flash position (pass) signal	ON or OFF	ON: Headlight dimmer switch in high flash position OFF: Headlight 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	w/ Rear Fog Light
      Front Fog Light SW	Front fog light switch signal	ON or OFF	ON: Front fog light switch on OFF: Front fog light switch off	w/ Front Fog Light
      Auto Light SW	Headlight dimmer switch AUTO position signal	ON or OFF	ON: Headlight dimmer switch in AUTO position OFF: Headlight dimmer switch not in AUTO position	-
      Head Light SW (Head)	Headlight dimmer switch head position signal	ON or OFF	ON: Headlight dimmer switch in head position OFF: Headlight dimmer switch not in head position	-
      Head Light SW (Tail)	Headlight dimmer switch tail position signal	ON or OFF	ON: Headlight dimmer switch in tail or head position OFF: Headlight dimmer switch in neither tail nor head position	-

      
      Body Electrical > Main Body > Data List

      Tester Display
      Dimmer SW
      Passing Light SW
      Rear Fog Light SW
      Front Fog Light SW
      Auto Light SW
      Head Light SW (Head)
      Head Light SW (Tail)

      Result
      Proceed to OK NG

   
   

   OK

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

   NG

2. INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY (LIGHT CONTROL SWITCH, DIMMER SWITCH)

   
   

   1. Remove the headlight dimmer switch assembly.

      Click here

   2. Inspect the headlight dimmer switch assembly.

      Click here

      Result
      Proceed to OK NG

   
   

   NG

   REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY Click here

   OK

3. CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER SWITCH ASSEMBLY - MAIN BODY ECU [MULTIPLEX NETWORK BODY ECU] AND BODY GROUND)

   
   

   1. Disconnect the I126*1 or I31*2 headlight dimmer switch assembly connector.

      *1: for LH Side

      *2: for RH Side

   2. Disconnect the I48 main body ECU (multiplex network body ECU) connector.

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

      Standard Resistance
      for LH Side
      Tester Connection Condition Specified Condition I48-22 (TAIL) - I126-18 (T) Always Below 1 Ω I48-12 (HEAD) - I126-19 (H) Always Below 1 Ω I48-8 (A) - I126-20 (A) Always Below 1 Ω I48-24 (HU) - I126-14 (HU) Always Below 1 Ω I48-10 (HF) - I126-17 (HF) Always Below 1 Ω I48-26 (FFOG) - I26-9 (BFG)*1 Always Below 1 Ω I48-23 (RFOG) - I126-7 (B)*2 Always Below 1 Ω I126-8 (LFG) - Body ground Always Below 1 Ω I126-15 (EL) - Body ground Always Below 1 Ω I48-22 (TAIL) - Body ground Always 10 kΩ or higher I48-12 (HEAD) - Body ground Always 10 kΩ or higher I48-8 (A) - Body ground Always 10 kΩ or higher I48-24 (HU) - Body ground Always 10 kΩ or higher I48-10 (HF) - Body ground Always 10 kΩ or higher I48-26 (FFOG) - Body ground*1 Always 10 kΩ or higher I48-23 (RFOG) - Body ground*2 Always 10 kΩ or higher *1: w/ Front Fog Light *2: w/ Rear Fog Light
      for RH Side
      Tester Connection Condition Specified Condition I48-22 (TAIL) - I31-13 (T) Always Below 1 Ω I48-12 (HEAD) - I31-12 (H) Always Below 1 Ω I48-8 (A) - I31-11 (A) Always Below 1 Ω I48-24 (HU) - I31-17 (HU) Always Below 1 Ω I48-10 (HF) - I31-14 (HF) Always Below 1 Ω I48-26 (FFOG) - I31-2 (BFG)*1 Always Below 1 Ω I48-23 (RFOG) - I31-4 (B)*2 Always Below 1 Ω I31-3 (LFG) - Body ground Always Below 1 Ω I31-16 (EL) - Body ground Always Below 1 Ω I48-22 (TAIL) - Body ground Always 10 kΩ or higher I48-12 (HEAD) - Body ground Always 10 kΩ or higher I48-8 (A) - Body ground Always 10 kΩ or higher I48-24 (HU) - Body ground Always 10 kΩ or higher I48-10 (HF) - Body ground Always 10 kΩ or higher I48-26 (FFOG) - Body ground*1 Always 10 kΩ or higher I48-23 (RFOG) - Body ground*2 Always 10 kΩ or higher *1: w/ Front Fog Light *2: w/ Rear Fog Light

      Result
      Proceed to OK NG

   
   

   OK

   REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) for LHD: REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) for RHD: REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR