LIGHTING SYSTEM Headlight Dimmer Switch Circuit

DESCRIPTION

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

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

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

• Front fog light switch position is on or off*1

• Rear fog light switch position is on or off

• *1: w/ Front Fog Light

WIRING DIAGRAM

1. for Light Control Switch LH Side Type

   

2. for Light Control Switch RH Side Type

   

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 display on the GTS.

      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 (pass) position OFF: Dimmer switch in low position	-
      Passing Light SW	Dimmer switch high flash (pass) position signal/ON or OFF	ON: Dimmer switch in high flash (pass) position OFF: Dimmer switch not in high flash (pass) 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*1	Front fog light switch signal/ON or OFF	ON: Front fog light switch on OFF: Front fog light switch off	-
      Light Auto 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	-
      Headlight SW	Light control switch head position signal/ON or OFF	ON: Light control switch in head position OFF: Light control switch not in head position	-
      Taillight SW	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	-

      
      

      • *1: w/ Front Fog Light

      OK
      Normal conditions listed above are displayed.

   
   

   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 as a result of monitoring the Data List.

   
   

   1. Remove the headlight dimmer switch assembly Click here.

   2. 

      Text in Illustration

      *a	Component without harness connected: (Headlight Dimmer Switch Assembly)

      for Light Control Switch LH Side Type:

      
      

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

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

         
         

         • *1: w/ Automatic Light Control

         • *2: w/ Front Fog Light

         OK
         Headlight dimmer switch assembly is normal.

   3. 

      Text in Illustration

      *a	Component without harness connected: (Headlight Dimmer Switch Assembly)

      for Light Control Switch RH Side Type:

      
      

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

         Standard Resistance
         Light Control Switch Tester Connection Condition Specified Condition 13 (T) - 19 (EL) Light control switch off 10 kΩ or higher 12 (A)*1 - 19 (EL) Light control switch off 10 kΩ or higher 11 (H) - 19 (EL) Light control switch off 10 kΩ or higher 13 (T) - 19 (EL) Light control switch in tail position Below 1 Ω 13 (T) - 19 (EL) Light control switch in head position Below 1 Ω 11 (H) - 19 (EL) Light control switch in head position Below 1 Ω 12 (A)*1 - 19 (EL) Light control switch in AUTO position Below 1 Ω
         Dimmer Switch Tester Connection 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 14 (HF) - 19 (EL) Dimmer switch in high flash position Below 1 Ω
         Front Fog Light Switch*2 Tester Connection Condition Specified Condition 7 (BFG) - 8 (LFG) Front fog light switch off 10 kΩ or higher 7 (BFG) - 8 (LFG) Front fog light switch on Below 1 Ω
         Rear Fog Light Switch Tester Connection Condition Specified Condition 9 (B) - 8 (LFG) Rear fog light switch off 10 kΩ or higher 9 (B) - 8 (LFG) Rear fog light switch on Below 1 Ω

         
         

         • *1: w/ Automatic Light Control

         • *2: w/ Front Fog Light

         OK
         Headlight dimmer switch assembly is normal.

   
   

   NG

   REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY Click here

   OK

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

   
   

   1. Disconnect the L201 main body ECU (multiplex network body ECU) connector.

   2. for Light Control Switch LH Side Type:

      
      

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

         Standard Resistance

         Tester Connection Condition Specified Condition L47-2 (B) - L201-1 (RFOG) Always Below 1 Ω L47-4 (BFG)*2 - L201-27 (FFOG)*2 Always Below 1 Ω L47-11 (HU) - L201-5 (HU) Always Below 1 Ω L47-17 (HF) - L201-8 (HF) Always Below 1 Ω L47-18 (T) - L201-30 (TAIL) Always Below 1 Ω L47-19 (A)*1 - L201-28 (A)*1 Always Below 1 Ω L47-20 (H) - L201-29 (HEAD) Always Below 1 Ω L47-2 (B) - Body ground Always 10 kΩ or higher L47-4 (BFG)*2 - Body ground Always 10 kΩ or higher L47-11 (HU) - Body ground Always 10 kΩ or higher L47-17 (HF) - Body ground Always 10 kΩ or higher L47-18 (T) - Body ground Always 10 kΩ or higher L47-19 (A)*1 - Body ground Always 10 kΩ or higher L47-20 (H) - Body ground Always 10 kΩ or higher L47-12 (EL) - Body ground Always Below 1 Ω L47-3 (LFG) - Body ground Always Below 1 Ω

         
         

         • *1: w/ Automatic Light Control

         • *2: w/ Front Fog Light

   3. for Light Control Switch RH Side Type:

      
      

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

         Standard Resistance

         Tester Connection Condition Specified Condition L47-9 (B) - L201-1 (RFOG) Always Below 1 Ω L47-7 (BFG)*2 - L201-27 (FFOG)*2 Always Below 1 Ω L47-20 (HU) - L201-5 (HU) Always Below 1 Ω L47-14 (HF) - L201-8 (HF) Always Below 1 Ω L47-13 (T) - L201-30 (TAIL) Always Below 1 Ω L47-12 (A)*1 - L201-28 (A)*1 Always Below 1 Ω L47-11 (H) - L201-29 (HEAD) Always Below 1 Ω L47-9 (B) - Body ground Always 10 kΩ or higher L47-7 (BFG)*2 - Body ground Always 10 kΩ or higher L47-20 (HU) - Body ground Always 10 kΩ or higher L47-14 (HF) - Body ground Always 10 kΩ or higher L47-13 (T) - Body ground Always 10 kΩ or higher L47-12 (A)*1 - Body ground Always 10 kΩ or higher L47-11 (H) - Body ground Always 10 kΩ or higher L47-19 (EL) - Body ground Always Below 1 Ω L47-8 (LFG) - Body ground Always Below 1 Ω

         
         

         • *1: w/ Automatic Light Control

         • *2: w/ Front Fog Light

   
   

   OK

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

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR