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

WIRING DIAGRAM

1. for LHD, RHD Light Control Switch LH Side Type:

   

2. for RHD Light Control Switch RH Side Type:

   

PROCEDURE

1. READ VALUE USING INTELLIGENT TESTER

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the power switch on (IG).

   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 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.

   
   

   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. 

      Text in Illustration

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

      Remove the headlight dimmer switch assembly Click here.

   2. 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.

   3. 

      Text in Illustration

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

      Remove the headlight dimmer switch assembly Click here.

   4. 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.

   
   

   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.

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

   3. 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

   
   

   OK

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

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR