Operating Light Control Rheostat does not Change Light Brightness [11/2015 - ]: Procedure

1. Confirm the symptoms.

   Result

   Result	Proceed to
   Meter illumination does not change when operating the light control rheostat.	A
   Dimmer function cannot be canceled.	B

Result: 

B 

See step  5

Result: 

A 

See step  2

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Combination Meter / Data List.
5. Check the values by referring to the table below.
   COMBINATION METER
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Rheostat value	Light control rheostat/Min.: 0 (dark), Max.: 100 (bright)	Light control rheostat value 0 (dark)	The value changes with rheostat operation
   		Light control rheostat value 100 (bright)

   OK

   The value displayed on the Techstream gradually changes with actual rheostat knob operation.

Result: 

OK 

REPLACE COMBINATION METER ASSEMBLY 

Refer to REMOVAL [11/2015 - ] )

Result: 

NG 

See step  3

1. Remove the light control rheostat (Refer to REMOVAL [11/2015 - ] ).

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   6 (E) - 7 (TR)	Light control rheostat is fully turned downwards (MIN.)	Below 50 Ω
   	Light control rheostat position is between MIN. and MAX.	The value changes gradually (Between 0 to 12 kΩ)
   	Light control rheostat is fully turned upwards (MAX.)	8 to 12 kΩ

   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Light Control Rheostat)

Result: 

NG 

REPLACE LIGHT CONTROL RHEOSTAT 

Refer to REMOVAL [11/2015 - ] )

Result: 

OK 

See step  4

1. Disconnect the G1 combination meter assembly connector.
2. Disconnect the G29 light control rheostat connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G1-17 (SW2) - G29-7 (TR)	Always	Below 1 Ω
   G1-17 (SW2) - Body ground	Always	10 kΩ or higher
   G1-19 (SW3) - G29-6 (E)	Always	Below 1 Ω
   G1-19 (SW3) - Body ground	Always	10 kΩ or higher

Result: 

OK 

REPLACE COMBINATION METER ASSEMBLY 

Refer to REMOVAL [11/2015 - ] )

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR 

1. Connect the Techstream to the DLC3.
2. Turn the ignition switch to ON (IG).
3. Turn the Techstream on.
4. Enter the following menus: Body Electrical / Combination Meter / Data List.
5. Check the values by referring to the table below.
   COMBINATION METER
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   Tail Cancel SW	Tail cancel switch/OFF or ON	OFF: Tail cancel switch off	Dimming of dash lights is possible
   		ON: Tail cancel switch on	Dimming of dash lights is canceled

   HINT: 

   The tail cancel switch is operated by turning the light control rheostat knob fully upward.

   OK

   Condition displayed on the Techstream is the same as the actual light control rheostat knob position.

Result: 

OK 

REPLACE COMBINATION METER ASSEMBLY 

Refer to REMOVAL [11/2015 - ] )

Result: 

NG 

See step  6

1. Remove the light control rheostat (Refer to REMOVAL [11/2015 - ] ).

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   8 (TC) - 9 (T)	Light control rheostat position is not fully turned upwards (Tail cancel switch is off)	Below 50 Ω
   	Light control rheostat is fully turned upwards (Tail cancel switch is on)	8 to 12 kΩ

   TEXT IN ILLUSTRATION
   
   

   *a	Component without harness connected (Light Control Rheostat)

Result: 

NG 

REPLACE LIGHT CONTROL RHEOSTAT 

Refer to REMOVAL [11/2015 - ] )

Result: 

OK 

See step  7

1. Disconnect the G1 combination meter assembly connector.
2. Disconnect the G29 light control rheostat connector.
3. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   G1-18 (SW1) - G29-9 (T)	Always	Below 1 Ω
   G1-18 (SW1) - Body ground	Always	10 kΩ or higher
   G1-16 (TC) - G29-8 (TC)	Always	Below 1 Ω
   G1-16 (TC) - Body ground	Always	10 kΩ or higher

Result: 

OK 

REPLACE COMBINATION METER ASSEMBLY 

Refer to REMOVAL [11/2015 - ] )

Result: 

NG 

REPAIR OR REPLACE HARNESS OR CONNECTOR