Operating Light Control Rheostat does not Change Light Brightness: Procedure

1. Confirm the symptoms.
   RESULT
   
   

   Result	Proceed to
   Meter illumination does not change when operate the light control rheostat knob	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 engine 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
   Light Control Rheostat	Light control rheostat/Min.: 0%, Max.: 100%	Turn the light control rheostat knob fully counterclockwise (0%)	-
   		Turn the light control rheostat knob fully clockwise (100%)

   OK

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

NG → See step   4 

OK: Go to next step 

1. Connect the Techstream to the DLC3.
2. Turn the engine 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: Light control rheostat position is except below	-
   		ON: Turn the light control rheostat knob fully clockwise (Tail cancel switch is ON)	-

   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: Light Control Rheostat Connector Terminal Identification

   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
   1 (E) - 4 (RV)	Turn the rheostat knob fully clockwise (MAX.)	8 to 12 kΩ
   1 (E) - 4 (RV)	Rheostat knob is between MIN. and MAX.	The value changes gradually (Between approx. 0 to 8 kΩ)
   1 (E) - 4 (RV)	Turn the rheostat knob fully counterclockwise (MIN.)	Approx. 0 Ω

   TEXT IN ILLUSTRATION
   
   

   *1	Component without harness connected (Light Control Rheostat)

NG → See step   10 

OK: Go to next step 

1. Disconnect the J34 and J15 connectors.
   Fig 2: J34 And J15 Connector Terminal Identification

   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
   J34-14 (ET) - J15-1 (E)	Always	Below 1 Ω
   J34-9 (ILL+) - J15-3 (T)	Always	Below 1 Ω
   J34-21 (TR) - J15-4 (RV)	Always	Below 1 Ω
   J15-1 (E) - Body ground	Always	10 kΩ or higher
   J15-3 (T) - Body ground	Always	10 kΩ or higher
   J15-4 (RV) - Body ground	Always	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Combination Meter Assembly)
   *2	Front view of wire harness connector (to Light Control Rheostat)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   9 

1. Connect the Techstream to the DLC3.
2. Turn the engine 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: Light control rheostat position is except below	-
   		ON: Turn the light control rheostat knob fully clockwise (Tail cancel switch is ON)	-

   OK

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

NG → See step   7 

OK → See step   9 

1. Remove the light control rheostat.
   Fig 3: Light Control Rheostat Connector Terminal Identification

   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
   2 (TC) - 3 (T)	Light control rheostat knob position is except below	Below 1 Ω
   2 (TC) - 3 (T)	Turn the light control rheostat knob fully clockwise (Tail cancel switch is ON)	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	Component without harness connected (Light Control Rheostat)

NG → See step   10 

OK: Go to next step 

1. Disconnect the J34 and J15 connectors.
   Fig 4: J34 And J15 Connector Terminal Identification

   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
   J34-8 (TC) - J15-2 (TC)	Always	Below 1 Ω
   J15-2 (TC) - Body ground	Always	10 kΩ or higher
   J34-9 (ILL+) - J15-3 (T)	Always	Below 1 Ω
   J15-3 (T) - Body ground	Always	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	Front view of wire harness connector (to Combination Meter Assembly)
   *2	Front view of wire harness connector (to Light Control Rheostat)

NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

OK → See step   9