LIGHTING SYSTEM Headlight Dimmer Switch Circuit

DESCRIPTION

The main body ECU receives the following signals:

• Headlight dimmer switch tail, head, AUTO*1, high or high flash signal

• Front fog light switch signal*2

• Rear fog light switch signal*3

• *1: w/ Automatic Light Control System

• *2: w/ Front Fog Light

• *3: w/ Rear Fog Light

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING INTELLIGENT TESTER (HEADLIGHT DIMMER SWITCH)

   
   

   1. Using the intelligent tester, read the Data List Click here.

      Main Body

      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*3	Rear fog light switch signal / ON or OFF	ON: Rear fog light switch on OFF: Rear fog light switch off	-
      Front Fog Light SW*2	Front fog light switch signal / ON or OFF	ON: Front fog light switch on OFF: Front fog light switch off	-
      Auto Light SW*1	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	-

      
      

      • *1: w/ Automatic Light Control System

      • *2: w/ Front Fog Light

      • *3: w/ Rear Fog Light

      OK
      The display is as specified in the normal condition column.

   
   

   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

   
   

   1. Remove the headlight dimmer switch Click here.

      

      Text in Illustration

      *A

      for Headlight Dimmer Switch LH Side Type

      *B

      for Headlight Dimmer Switch RH Side Type

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

      Standard Resistance
      for Headlight Dimmer Switch LH Side Type
      Tester Connection Switch Condition Specified Condition 2 (B) - 3 (LFG)*3 Rear fog light switch on Below 1 Ω 4 (BFG) - 3 (LFG)*2 Fog light switch on Below 1 Ω 11 (HU) - 12 (EL) Headlight dimmer switch high Below 1 Ω Headlight dimmer switch high flash 17 (HF) - 12 (EL) Headlight dimmer switch high flash Below 1 Ω 18 (T) - 12 (EL) Headlight dimmer switch tail Below 1 Ω Headlight dimmer switch head 19 (A) - 12 (EL)*1 Headlight dimmer switch AUTO Below 1 Ω 20 (H) - 12 (EL) Headlight dimmer switch head Below 1 Ω 2 (B) - 3 (LFG)*3 Rear fog light switch off 10 kΩ or higher 4 (BFG) - 3 (LFG)*2 Fog light switch off 10 kΩ or higher 18 (T) - 12 (EL) Headlight dimmer switch off 10 kΩ or higher 19 (A) - 12 (EL)*1 20 (H) - 12 (EL)
      for Headlight Dimmer Switch RH Side Type
      Tester Connection Switch Condition Specified Condition 9 (B) - 8 (LFG)*3 Rear fog light switch on Below 1 Ω 7 (BFG) - 8 (LFG)*2 Fog light switch on Below 1 Ω 20 (HU) - 19 (EL) Headlight dimmer switch high Below 1 Ω Headlight dimmer switch high flash 14 (HF) - 19 (EL) Headlight dimmer switch high flash Below 1 Ω 13 (T) - 19 (EL) Headlight dimmer switch tail Below 1 Ω Headlight dimmer switch head 12 (A) - 19 (EL)*1 Headlight dimmer switch AUTO Below 1 Ω 11 (H) - 19 (EL) Headlight dimmer switch head Below 1 Ω 9 (B) - 8 (LFG)*3 Rear fog light switch off 10 kΩ or higher 7 (BFG) - 8 (LFG)*2 Fog light switch off 10 kΩ or higher 13 (T) - 19 (EL) Headlight dimmer switch off 10 kΩ or higher 12 (A) - 19 (EL)*1 11 (H) - 19 (EL)

      
      

      • *1: w/ Automatic Light Control System

      • *2: w/ Front Fog Light

      • *3: w/ Rear Fog Light

   
   

   NG

   REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY Click here

   OK

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

   
   

   1. Disconnect the G44 headlight dimmer switch connector.

   2. Disconnect the G63 and G64 main body ECU connectors.

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

      Standard Resistance
      for Headlight Dimmer Switch LH Side Type
      Tester Connection Condition Specified Condition G44-2 (B) - G63-23 (RFOG)*3 Always Below 1 Ω G44-4 (BFG) - G64-27 (FFOG)*2 Always Below 1 Ω G44-11 (HU) - G64-5 (HU) Always Below 1 Ω G44-17 (HF) - G64-8 (HF) Always Below 1 Ω G44-18 (T) - G64-30 (TAIL) Always Below 1 Ω G44-19 (A) - G64-28 (A)*1 Always Below 1 Ω G44-20 (H) - G64-29 (HEAD) Always Below 1 Ω G44-3 (LFG) - Body ground*2, *3 Always Below 1 Ω G44-12 (E) - Body ground Always Below 1 Ω G44-2 (B) - Body ground*3 Always 10 kΩ or higher G44-4 (BFG) - Body ground*2 Always 10 kΩ or higher G44-11 (HU) - Body ground Always 10 kΩ or higher G44-17 (HF) - Body ground Always 10 kΩ or higher G44-18 (T) - Body ground Always 10 kΩ or higher G44-19 (A) - Body ground*1 Always 10 kΩ or higher G44-20 (H) - Body ground Always 10 kΩ or higher
      for Headlight Dimmer Switch RH Side Type
      Tester Connection Condition Specified Condition G44-9 (B) - G63-23 (RFOG)*3 Always Below 1 Ω G44-7 (BFG) - G64-27 (FFOG)*2 Always Below 1 Ω G44-20 (HU) - G64-5 (HU) Always Below 1 Ω G44-14 (HF) - G64-8 (HF) Always Below 1 Ω G44-13 (T) - G64-30 (TAIL) Always Below 1 Ω G44-12 (A) - G64-28 (A)*1 Always Below 1 Ω G44-11 (H) - G64-29 (HEAD) Always Below 1 Ω G44-8 (LFG) - Body ground*2, *3 Always Below 1 Ω G44-19 (EL) - Body ground Always Below 1 Ω G44-9 (B) - Body ground*3 Always 10 kΩ or higher G44-7 (BFG) - Body ground*2 Always 10 kΩ or higher G44-20 (HU) - Body ground Always 10 kΩ or higher G44-14 (HF) - Body ground Always 10 kΩ or higher G44-13 (T) - Body ground Always 10 kΩ or higher G44-12 (A) - Body ground*1 Always 10 kΩ or higher G44-11 (H) - Body ground Always 10 kΩ or higher

      
      

      • *1: w/ Automatic Light Control System

      • *2: w/ Front Fog Light

      • *3: w/ Rear Fog Light

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

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