LIGHTING SYSTEM Headlight Dimmer Switch Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) receives the following switch information:

• Light control switch in off, tail, head or AUTO position

• Dimmer switch in high, low or high flash (pass) position

• Fog light switch in rear or off position (w/ Rear Fog Light)

WIRING DIAGRAM

1. for Light Control Switch LH Side Type

   

2. for Light Control Switch RH Side Type

   

CAUTION / NOTICE / HINT

PROCEDURE

1. READ VALUE USING GTS

   
   

   1. Connect the GTS to the DLC3.

   2. Turn the power switch on (IG).

   3. Turn the GTS on.

   4. Enter the following menus: Body Electrical / Main Body / Data List.

   5. Read the Data List according to the display on the GTS.

      
      Body Electrical > Main Body > Data List

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

      
      Body Electrical > Main Body > Data List

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

      OK
      Normal conditions listed above are displayed.

      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

   Tech Tips

   Inspect the items that did not change when reading the Data List.

   
   

   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 K2 main body ECU (multiplex network body ECU) connector.

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

      Standard Resistance
      for Light Control Switch LH Side Type Tester Connection Condition Specified Condition K23-9 (B) - K2-23 (RFOG)* Always Below 1 Ω K23-18 (HU) - K2-24 (HU) Always Below 1 Ω K23-21 (HF) - K2-10 (HF) Always Below 1 Ω K23-22 (T) - K2-22 (TAIL) Always Below 1 Ω K23-23 (H) - K2-12 (HEAD) Always Below 1 Ω K23-24 (A) - K2-8 (A) Always Below 1 Ω K23-9 (B) or K2-23 (RFOG) - Body ground* Always 10 kΩ or higher K23-18 (HU) or K2-24 (HU) - Body ground Always 10 kΩ or higher K23-21 (HF) or K2-10 (HF) - Body ground Always 10 kΩ or higher K23-22 (T) or K2-22 (TAIL) - Body ground Always 10 kΩ or higher K23-23 (H) or K2-12 (HEAD) - Body ground Always 10 kΩ or higher K23-24 (A) or K2-8 (A) - Body ground Always 10 kΩ or higher K23-19 (EL) - Body ground Always Below 1 Ω K23-10 (LFG) - Body ground* Always Below 1 Ω
      for Light Control Switch RH Side Type Tester Connection Condition Specified Condition K23-4 (B) - K2-23 (RFOG)* Always Below 1 Ω K23-19 (HU) - K2-24 (HU) Always Below 1 Ω K23-16 (HF) - K2-10 (HF) Always Below 1 Ω K23-15 (T) - K2-22 (TAIL) Always Below 1 Ω K23-14 (H) - K2-12 (HEAD) Always Below 1 Ω K23-13 (A) - K2-8 (A) Always Below 1 Ω K23-4 (B) or K2-23 (RFOG) - Body ground* Always 10 kΩ or higher K23-19 (HU) or K2-24 (HU) - Body ground Always 10 kΩ or higher K23-16 (HF) or K2-10 (HF) - Body ground Always 10 kΩ or higher K23-15 (T) or K2-22 (TAIL) - Body ground Always 10 kΩ or higher K23-14 (H) or K2-12 (HEAD) - Body ground Always 10 kΩ or higher K23-13 (A) or K2-8 (A) - Body ground Always 10 kΩ or higher K23-18 (EL) - Body ground Always Below 1 Ω K23-3 (LFG) - Body ground* Always Below 1 Ω

      
      

      • *: w/ Rear Fog Light

      Result
      Proceed to OK NG

   
   

   OK

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

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR