Headlight Dimmer Switch Circuit [03/2017 - ]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Data List.
5. Read the display on the Techstream.
   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	-
   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	-
   Lighting Hi	Light control switch HEAD (Hi) position signal / ON or OFF	ON: Headlight high beam on OFF: Headlight high beam off	-

   • *: w/ Front Fog Light

   OK

   The display is as specified in the normal condition column.

   Result

   Result	Proceed to
   OK	A
   NG (Dimmer switch)	B
   NG (Fog switch and light control switch)	C

Result: 

A 

REPLACE MAIN BODY ECU (NETWORK GATEWAY ECU). Refer to  REMOVAL [06/2016 - ] 

Result: 

C 

See step  4

Result: 

B 

See step  2

1. Remove the headlight dimmer switch assembly.

   Refer to REMOVAL [06/2016 - ]

2. Inspect the headlight dimmer switch assembly.

   Refer to INSPECTION [03/2017 - ]

Result: 

NG 

REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY. Refer to  REMOVAL [06/2016 - ] 

Result: 

OK 

See step  3

1. Disconnect the 3B instrument panel junction block assembly connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   D50-17 (HF) - 3B-15	Always	Below 1 Ω
   D50-11 (HU) - 3B-30	Always	Below 1 Ω
   D50-12 (EL) - Body ground	Always	Below 1 Ω

   Standard Resistance (Check for Short)

   Tester Connection	Condition	Specified Condition
   D50-17 (HF) - Body ground	Always	10 kΩ or higher
   D50-11 (HU) - Body ground	Always	10 kΩ or higher

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [03/2017 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

1. Remove the headlight dimmer switch assembly.

   Refer to REMOVAL [06/2016 - ]

2. Inspect the headlight dimmer switch assembly.

   Refer to INSPECTION [03/2017 - ]

Result: 

NG 

REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY. Refer to  REMOVAL [06/2016 - ] 

Result: 

OK 

See step  5

1. Disconnect the D5 and A73 main body ECU (network gateway ECU) connector.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   D50-4 (BFG) - D5-24 (FFOG)*	Always	Below 1 Ω
   D50-20 (H) - D5-2 (HEAD1)	Always	Below 1 Ω
   D50-20 (H) - A73-12 (HEAD2)	Always	Below 1 Ω
   D50-19 (A) - D5-23 (A)	Always	Below 1 Ω
   D50-18 (T) - D5-25 (TAIL)	Always	Below 1 Ω
   D50-12 (EL) - Body ground	Always	Below 1 Ω
   D50-3 (LFG)* - Body ground	Always	Below 1 Ω

   Standard Resistance (Check for Short)

   Tester Connection	Condition	Specified Condition
   D50-4 (BFG)* - Body ground	Always	10 kΩ or higher
   D50-20 (H) - Body ground	Always	10 kΩ or higher
   D50-19 (A) - Body ground	Always	10 kΩ or higher
   D50-18 (T) - Body ground	Always	10 kΩ or higher

   • *: w/ Front Fog Light

Result: 

OK 

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE [03/2017 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR