Headlight Dimmer Switch Circuit [08/2019 - 07/2020]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the power switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Data List.
5. Read the Data List according to the display on the Techstream.

   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	-
   Front Fog Light SW	Fog light switch front position signal	OFF or ON	OFF: Fog light switch off ON: Fog light switch in front position	Light control switch in tail position w/ Front 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 not in tail or head position ON: Light control switch in tail or head position	-

   Body Electrical > Main Body > Data List 

   Tester Display
   Dimmer SW
   Passing Light SW
   Front 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

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [08/2019 - ] 

Result: 

NG 

See step  2

1. Remove the headlight dimmer switch assembly.

   Refer to REMOVAL [08/2019 - ]

2. Inspect the headlight dimmer switch assembly.

   Refer to INSPECTION [08/2019 - 07/2020]

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY. Refer to  REMOVAL [08/2019 - ] 

Result: 

OK 

See step  3

1. Disconnect the J8 main body ECU (multiplex network body ECU) connector.
2. Measure the resistance according to the value (s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   J28-18 (T) - J8-22 (TAIL)	Always	Below 1 Ω
   J28-19 (H) - J8-12 (HEAD)	Always	Below 1 Ω
   J28-20 (A) - J8-8 (A)	Always	Below 1 Ω
   J28-14 (HU) - J8-24 (HU)	Always	Below 1 Ω
   J28-17 (HF) - J8-10 (HF)	Always	Below 1 Ω
   J28-9 (BFG) - J8-26 (FFOG)*	Always	Below 1 Ω
   J28-18 (T) or J8-22 (TAIL) - Body ground	Always	10 kΩ or higher
   J28-19 (H) or J8-12 (HEAD) - Body ground	Always	10 kΩ or higher
   J28-20 (A) or J8-8 (A) - Body ground	Always	10 kΩ or higher
   J28-14 (HU) or J8-24 (HU) - Body ground	Always	10 kΩ or higher
   J28-17 (HF) or J8-10 (HF) - Body ground	Always	10 kΩ or higher
   J28-9 (BFG) or J8-26 (FFOG) - Body ground*	Always	10 kΩ or higher
   J28-8 (LFG) - Body ground	Always	Below 1 Ω
   J28-15 (EL) - Body ground	Always	Below 1 Ω

   1. *: w/ Front Fog Light

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [08/2019 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR