LIGHTING SYSTEM Headlight Dimmer Switch Circuit

DESCRIPTION

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

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

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

• Front fog light switch is in on or off position

• Rear fog light switch is in on or off position

WIRING DIAGRAM

1. for LHD

   

2. for RHD

   

INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING INTELLIGENT TESTER

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the ignition switch to ON.

   3. Turn the intelligent tester on.

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

   5. 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 position 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

   INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY Click here

   OK

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

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. for LHD:

      
      
      1. 

         Text in Illustration

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

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

         Standard Resistance
         Light Control Switch Tester Connection Switch Condition Specified Condition 15 (EL) - 18 (T) Light control switch off 10 kΩ or higher 18 (T) - 20 (A) Light control switch off 10 kΩ or higher 20 (A) - 19 (H) Light control switch off 10 kΩ or higher 15 (EL) - 18 (T) Light control switch in tail position Below 1 Ω 15 (EL) - 18 (T) Light control switch in head position Below 1 Ω 18 (T) - 19 (H) Light control switch in head position Below 1 Ω 15 (EL) - 20 (A) Light control switch in AUTO position Below 1 Ω
         Dimmer Switch Tester Connection Switch Condition Specified Condition 14 (HU) - 15 (EL) Dimmer switch in low position 10 kΩ or higher 14 (HU) - 15 (EL) Dimmer switch in high position Below 1 Ω 15 (EL) - 17 (HF) Dimmer switch in high flash position Below 1 Ω
         Front Fog Light Switch Tester Connection Switch Condition Specified Condition 8 (LFG) - 9 (BFG) Fog light switch off 10 kΩ or higher 8 (LFG) - 9 (BFG) Fog light switch on Below 1 Ω
         Rear Fog Light Switch*1 Tester Connection Switch Condition Specified Condition 7 (B) - 8 (LFG) Rear fog light switch off 10 kΩ or higher 7 (B) - 8 (LFG) Rear fog light switch on Below 1 Ω

         *1: w/ Rear Fog Light

   3. for RHD:

      
      
      1. 

         Text in Illustration

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

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

         Standard Resistance
         Light Control Switch Tester Connection Switch Condition Specified Condition 16 (EL) - 13 (T) Light control switch off 10 kΩ or higher 13 (T) - 11 (A) Light control switch off 10 kΩ or higher 11 (A) - 12 (H) Light control switch off 10 kΩ or higher 16 (EL) - 13 (T) Light control switch in tail position Below 1 Ω 16 (EL) - 13 (T) Light control switch in head position Below 1 Ω 13 (T) - 12 (H) Light control switch in head position Below 1 Ω 16 (EL) - 11 (A) Light control switch in AUTO position Below 1 Ω
         Dimmer Switch Tester Connection Switch Condition Specified Condition 17 (HU) - 16 (EL) Dimmer switch in low position 10 kΩ or higher 17 (HU) - 16 (EL) Dimmer switch in high position Below 1 Ω 16 (EL) - 14 (HF) Dimmer switch in high flash position Below 1 Ω
         Front Fog Light Switch Tester Connection Switch Condition Specified Condition 3 (LFG) - 2 (BFG) Fog light switch off 10 kΩ or higher 3 (LFG) - 2 (BFG) Fog light switch on Below 1 Ω

   
   

   NG

   REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY Click here

   OK

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

   
   

   1. Disconnect the I13 main body ECU (multiplex network body ECU) connector.

   2. for LHD:

      
      

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

         Standard Resistance

         Tester Connection Condition Specified Condition I25-9 (BFG) - I13-27 (FFOG) Always Below 1 Ω I25-7 (B) - I13-23 (RFOG)*1 Always Below 1 Ω I25-14 (HU) - I13-5 (HU) Always Below 1 Ω I25-17 (HF) - I13-8 (HF) Always Below 1 Ω I25-18 (T) - I13-30 (TAIL) Always Below 1 Ω I25-19 (H) - I13-29 (HEAD) Always Below 1 Ω I25-20 (A) - I13-28 (A) Always Below 1 Ω I25-9 (BFG) - Body ground Always 10 kΩ or higher I25-7 (B)*1 - Body ground Always 10 kΩ or higher I25-14 (HU) - Body ground Always 10 kΩ or higher I25-17 (HF) - Body ground Always 10 kΩ or higher I25-18 (T) - Body ground Always 10 kΩ or higher I25-19 (H) - Body ground Always 10 kΩ or higher I25-20 (A) - Body ground Always 10 kΩ or higher I25-15 (EL) - Body ground Always Below 1 Ω I25-8 (LFG) - Body ground Always Below 1 Ω

         
         

         • *1: w/ Rear Fog Light

   3. for RHD:

      
      

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

         Standard Resistance

         Tester Connection Condition Specified Condition I25-2 (BFG) - I13-27 (FFOG) Always Below 1 Ω I25-17 (HU) - I13-5 (HU) Always Below 1 Ω I25-14 (HF) - I13-8 (HF) Always Below 1 Ω I25-13 (T) - I13-30 (TAIL) Always Below 1 Ω I25-12 (H) - I13-29 (HEAD) Always Below 1 Ω I25-11 (A) - I13-28 (A) Always Below 1 Ω I25-2 (BFG) - Body ground Always 10 kΩ or higher I25-17 (HU) - Body ground Always 10 kΩ or higher I25-14 (HF) - Body ground Always 10 kΩ or higher I25-13 (T) - Body ground Always 10 kΩ or higher I25-12 (H) - Body ground Always 10 kΩ or higher I25-11 (A) - Body ground Always 10 kΩ or higher I25-16 (EL) - Body ground Always Below 1 Ω I25-3 (LFG) - Body ground Always Below 1 Ω

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

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