Operating Light Control Rheostat does not Change Light Brightness [06/2016 - ]: 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 / Combination Meter / Data List.
5. According to the display on the tester, read the Data List.
   COMBINATION METER
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Tail Cancel SW	Taillight relay / OFF or ON	OFF: Headlight dimmer switch (Light control switch) → OFF	-
   		ON: Headlight dimmer switch (Light control switch) → TAIL
   Rheostat value	Light control rheostat switch input / Min.: 0 Max.: 100	The volume value of the rheostat is displayed. 0 to 100	-

   OK

   The value displayed on the Techstream changes in accordance with the actual rheostat switch operation.

Result: 

OK 

REPLACE COMBINATION METER ASSEMBLY 

(Refer to REMOVAL [06/2016 - 03/2017] Refer to REMOVAL [03/2017 - ] )

Result: 

NG 

See step  2

1. Remove the light control rheostat (Refer to REMOVAL [06/2016 - ] ).

   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
   1 - 6	Cancel switch off → on	10 kΩ or higher → Below 1 Ω
   4 - 6	Always	4475 to 4946 Ω
   5 - 6	Light control rheostat fully up → Light control rheostat fully down	485 to 536 Ω → 4380 to 4841 Ω

   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Light Control Rheostat)

Result: 

NG 

REPLACE LIGHT CONTROL RHEOSTAT 

(Refer to REMOVAL [06/2016 - ] )

Result: 

OK 

See step  3

1. Disconnect the D7 combination meter assembly connector.
2. Disconnect the D2 light control rheostat connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance (Check for Open)

   Tester Connection	Condition	Specified Condition
   D7-30 (E) - D2-6	Always	Below 1 Ω
   D7-31 (TR) - D2-5	Always	Below 1 Ω
   D7-32 (T) - D2-4	Always	Below 1 Ω
   D7-33 (TC) - D2-1	Always	Below 1 Ω

   Standard Resistance (Check for Short)

   Tester Connection	Condition	Specified Condition
   D7-30 (E) or D2-6 - Body ground	Always	10 kΩ or higher
   D7-31 (TR) or D2-5 - Body ground	Always	10 kΩ or higher
   D7-32 (T) or D2-4 - Body ground	Always	10 kΩ or higher
   D7-33 (TC) or D2-1 - Body ground	Always	10 kΩ or higher

Result: 

OK 

REPLACE COMBINATION METER ASSEMBLY 

(Refer to REMOVAL [06/2016 - 03/2017] Refer to REMOVAL [03/2017 - ] )

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR