Operating Light Control Rheostat does not Change Light Brightness: Procedure

1. Confirm the symptoms.

   Result

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

B → See step   6 

A: Go to next step 

1. Connect the Techstream to the DLC3.
2. Turn the power switch 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.: 255 (bright)	The light control rheostat value 0 (dark)	The value changes with the rheostat operation
   		The light control rheostat value 255 (bright)

   OK

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

NG → See step   4 

OK: Go to next step 

1. Connect the Techstream to the DLC3.
2. Turn the power switch 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	-
   		ON: Tail cancel switch on	-

   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.

NG → See step   7 

OK → See step   9 

1. Remove the light control rheostat.
   Fig 1: Identifying Light Control Rheostat & Connector Terminals

   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 (E) - 3 (TR)	Turn the light control rheostat knob fully downwards (MIN.)	Below 50 Ω
   	Light control rheostat knob position is between MIN. and MAX.	The value changes gradually (Between 0 to 12 kΩ)
   	Turn the light control rheostat knob fully upwards (MAX.)	8 to 12 kΩ

   TEXT IN ILLUSTRATION
   
   

   *1	Component without harness connected (Light Control Rheostat)

NG → See step   10 

OK: Go to next step 

1. Disconnect the L27 and L59 connectors.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   L27-37 (SW2) - L59-3 (TR)	Always	Below 1 Ω
   L27-37 (SW2) - Body ground	Always	10 kΩ or higher
   L27-38 (SW3) - L59-1 (E)	Always	Below 1 Ω
   L27-38 (SW3) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   9 

1. Connect the Techstream to the DLC3.
2. Turn the power switch 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	-
   		ON: Tail cancel switch on	-

   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.

NG → See step   7 

OK: Go to next step 

1. Remove the light control rheostat.
   Fig 2: Identifying Light Control Rheostat (TC & T) Terminals

   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
   5 (TC) - 7 (T)	Light control rheostat position is except below	Below 50 Ω
   	Turn the light control rheostat knob fully upwards (Tail cancel switch is on)	8 to 12 kΩ

   TEXT IN ILLUSTRATION
   
   

   *1	Component without harness connected (Light Control Rheostat)

NG → See step   10 

OK: Go to next step 

1. Disconnect the L27 and L59 connectors.
2. Measure the resistance according to the value(s) in the table below.

   Standard Resistance

   Tester Connection	Condition	Specified Condition
   L27-36 (SW1) - L59-7 (T)	Always	Below 1 Ω
   L27-36 (SW1) - Body ground	Always	10 kΩ or higher
   L27-35 (TC) - L59-5 (TC)	Always	Below 1 Ω
   L27-35 (TC) - Body ground	Always	10 kΩ or higher

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   9