Headlight Dimmer Switch Circuit [04/2013 - 10/2016]: Procedure

1. Connect the Techstream to the DLC3.
2. Turn the engine switch on (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Main Body / Data List.
5. Read 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	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	Fog light switch front position signal	ON or OFF	ON: Fog light switch in front position OFF: Fog light switch off	*1
   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	-

   1. *1: w/ Front Fog Light

   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 [04/2013 - 06/2014]  , or refer to  PROBLEM SYMPTOMS TABLE [06/2014 - 08/2015]  , or refer to  PROBLEM SYMPTOMS TABLE [08/2015 - 10/2016] 

Result: 

NG 

See step  2

HINT: 

Inspect the items that did not change as a result of monitoring the Data List.

1. Remove the headlight dimmer switch assembly.

   Refer to REMOVAL [04/2013 - ]

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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   LIGHT CONTROL SWITCH
   
   

   Tester Connection	Condition	Specified Condition
   22 (T) - 19 (EL)	Light control switch off or DRL OFF	10 kΩ or higher
   23 (H) - 19 (EL)	Light control switch off or DRL OFF	10 kΩ or higher
   24 (A) - 19 (EL)	Light control switch off or DRL OFF	10 kΩ or higher
   22 (T) - 19 (EL)	Light control switch in tail position	Below 1 Ω
   22 (T) - 19 (EL)	Light control switch in head position	Below 1 Ω
   23 (H) - 19 (EL)	Light control switch in head position	Below 1 Ω
   24 (A) - 19 (EL)	Light control switch in AUTO position	Below 1 Ω

   DIMMER SWITCH
   
   

   Tester Connection	Condition	Specified Condition
   18 (HU) - 19 (EL)	Dimmer switch in high position	Below 1 Ω
   18 (HU) - 19 (EL)	Dimmer switch in high flash position	Below 1 Ω
   21 (HF) - 19 (EL)	Dimmer switch in high flash position	Below 1 Ω

   FOG LIGHT SWITCH*1
   
   

   Tester Connection	Condition	Specified Condition
   11 (BFG) - 10 (LFG)	Fog light switch off	10 kΩ or higher
   11 (BFG) - 10 (LFG)	Fog light switch in front position	Below 1 Ω

   1. *1: w/ Front Fog Light

   Result

   Proceed to
   OK
   NG

Result: 

NG 

REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY. Refer to  REMOVAL [04/2013 - ] 

Result: 

OK 

See step  3

1. Disconnect the K2 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
   K23-11 (BFG)*1 - K2-26 (FFOG)*1	Always	Below 1 Ω
   K23-18 (HU) - K2-24 (HU)	Always	Below 1 Ω
   K23-21 (HF) - K2-10 (HF)	Always	Below 1 Ω
   K23-22 (T) - K2-22 (TAIL)	Always	Below 1 Ω
   K23-23 (H) - K2-12 (HEAD)	Always	Below 1 Ω
   K23-24 (A) - K2-8 (A)	Always	Below 1 Ω
   K23-11 (BFG)*1 - Body ground	Always	10 kΩ or higher
   K23-18 (HU) - Body ground	Always	10 kΩ or higher
   K23-21 (HF) - Body ground	Always	10 kΩ or higher
   K23-22 (T) - Body ground	Always	10 kΩ or higher
   K23-23 (H) - Body ground	Always	10 kΩ or higher
   K23-24 (A) - Body ground	Always	10 kΩ or higher
   K23-19 (EL) - Body ground	Always	Below 1 Ω
   K23-10 (LFG)*1 - Body ground	Always	Below 1 Ω

   1. *1: w/ Front Fog Light

   Result

   Proceed to
   OK
   NG

Result: 

OK 

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to  REMOVAL [04/2013 - ] 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR