Headlight Dimmer Switch Circuit [09/2014 - ]: 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 Data List according to 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	-
   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 not in tail or head position	-

   OK

   Normal conditions listed above are displayed.

NG → See step   2 

OK → See step   4 

HINT: 

Inspect the items that did not change when reading the Data List.

1. Remove the headlight dimmer switch assembly. Refer to REMOVAL [09/2014 - ] .

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   LIGHT CONTROL SWITCH (W/ DRL OFF FUNCTION)
   
   

   Tester Connection	Condition	Specified Condition
   15 (EL) - 18 (T)	Light control switch off (DRL OFF position)	10 kΩ or higher
   18 (T) - 20 (A)	Light control switch off (DRL OFF position)	10 kΩ or higher
   20 (A) - 19 (H)	Light control switch off (DRL OFF position)	10 kΩ or higher
   15 (EL) - 18 (T)	Light control switch in tail position	Below 1 Ω
   15 (EL) - 18 (T)	Light control switch in head position	Below 1 Ω
   18 (T) - 19 (H)	Light control switch in head position	Below 1 Ω
   15 (EL) - 20 (A)	Light control switch in AUTO position	Below 1 Ω

   LIGHT CONTROL SWITCH (W/O DRL OFF FUNCTION)
   
   

   Tester Connection	Condition	Specified Condition
   15 (EL) - 18 (T)	Light control switch off	10 kΩ or higher
   18 (T) - 20 (A)	Light control switch off	10 kΩ or higher
   20 (A) - 19 (H)	Light control switch off	10 kΩ or higher
   15 (EL) - 18 (T)	Light control switch in tail position	Below 1 Ω
   15 (EL) - 18 (T)	Light control switch in head position	Below 1 Ω
   18 (T) - 19 (H)	Light control switch in head position	Below 1 Ω
   15 (EL) - 20 (A)	Light control switch in AUTO position	Below 1 Ω

   DIMMER SWITCH
   
   

   Tester Connection	Condition	Specified Condition
   14 (HU) - 15 (EL)	Dimmer switch in low position	10 kΩ or higher
   14 (HU) - 15 (EL)	Dimmer switch in high position	Below 1 Ω
   15 (EL) - 17 (HF)	Dimmer switch in high flash position	Below 1 Ω

   TEXT IN ILLUSTRATION
   
   

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

NG → See step   5 

OK: Go to next step 

1. Disconnect the I13 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
   I25-14 (HU) - I13-5 (HU)	Always	Below 1 Ω
   I25-17 (HF) - I13-8 (HF)	Always	Below 1 Ω
   I25-18 (T) - I13-30 (TAIL)	Always	Below 1 Ω
   I25-19 (H) - I13-29 (HEAD)	Always	Below 1 Ω
   I25-20 (A) - I13-28 (A)	Always	Below 1 Ω
   I25-14 (HU) - Body ground	Always	10 kΩ or higher
   I25-17 (HF) - Body ground	Always	10 kΩ or higher
   I25-18 (T) - Body ground	Always	10 kΩ or higher
   I25-19 (H) - Body ground	Always	10 kΩ or higher
   I25-20 (A) - Body ground	Always	10 kΩ or higher
   I25-15 (EL) - Body ground	Always	Below 1 Ω

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   6