Light Control Switch Circuit [08/2015 - 08/2017]: 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. According to the display on the Techstream, read the Data List.
   MAIN BODY
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Dimmer SW	Dimmer switch signal / ON or OFF	ON: Dimmer switch ON OFF: Dimmer switch OFF	-
   Passing Light SW	Passing light switch signal / ON or OFF	ON: Passing light switch ON OFF: Passing light switch OFF	-
   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	Auto light switch signal / ON or OFF	ON: Auto light switch ON OFF: Auto light switch OFF	-
   Head Light SW (Head)	Headlight switch signal / ON or OFF	ON: Headlight switch ON OFF: Headlight switch OFF	-
   Head Light SW (Tail)	Taillight switch signal / ON or OFF	ON: Taillight switch ON OFF: Taillight switch OFF	-

   OK

   When combination light switch operation is performed, the result will be the same as above.

Result: 

OK 

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE 

(Refer to PROBLEM SYMPTOMS TABLE [08/2015 - 08/2017] )

Result: 

NG 

See step  2

1. Remove the headlight dimmer switch assembly (Refer to REMOVAL [08/2015 - 08/2017] ).

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Switch Condition	Specified Condition
   18 (T) - 12 (EL)	Light control switch TAIL	Below 1 Ω
   	Light control switch HEAD	Below 1 Ω
   20 (H) - 12 (EL)	Light control switch HEAD	Below 1 Ω
   19 (A) - 12 (EL)	Light control switch AUTO	Below 1 Ω
   4 (BFG) - 3 (LFG)	Front fog light switch ON	Below 1 Ω
   17 (HF) - 12 (EL)	Dimmer switch High	Below 1 Ω
   11 (HU) - 12 (EL)	Dimmer switch Low	Below 1 Ω

3. Reinstall the headlight dimmer switch assembly.

Result: 

NG 

REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY 

(Refer to REMOVAL [08/2015 - 08/2017] )

Result: 

OK 

See step  3

1. Disconnect the H11 headlight dimmer switch assembly connector.

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

2. Disconnect the H3, H4 and DD main body ECU connectors.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H11-4 (BFG) - H3-28 (FFOG)	Always	Below 1 Ω
   H11-19 (A) - H4-21 (A)	Always	Below 1 Ω
   H11-20 (H) - H3-17 (HEAD)	Always	Below 1 Ω
   H11-18 (T) - H4-23 (TAIL)	Always	Below 1 Ω
   H11-17 (HF) - H4-13 (HF)	Always	Below 1 Ω
   H11-11 (HU) - DD-13 (HU)	Always	Below 1 Ω
   H11-4 (BFG) - Body ground	Always	10 kΩ or higher
   H11-19 (A) - Body ground	Always	10 kΩ or higher
   H11-20 (H) - Body ground	Always	10 kΩ or higher
   H11-18 (T) - Body ground	Always	10 kΩ or higher
   H11-17 (HF) - Body ground	Always	10 kΩ or higher
   H11-11 (HU) - Body ground	Always	10 kΩ or higher

4. Reconnect the main body ECU connectors.
5. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   H11-12 (EL) - Body ground	Always	Below 1 Ω
   H11-3 (LFG) - Body ground	Always	Below 1 Ω

6. Reconnect the headlight dimmer switch assembly connector.

Result: 

OK 

REPLACE MAIN BODY ECU 

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR