Operating Light Control Rheostat does not Change Light Brightness: Procedure

1. Confirm the symptoms.

   Result

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

B → See step   5 

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 Up SW	Light control rheostat up switch/OFF or ON	OFF: Light control rheostat up switch not pressed	-
   		ON: Light control rheostat up switch pressed
   Light Control Down SW	Light control rheostat down switch/ OFF or ON	OFF: Light control rheostat down switch not pressed	-
   		ON: Light control rheostat down switch pressed

   OK

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

NG → See step   3 

OK → See step   7 

1. Remove the light control rheostat.

   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
   3 (UP) - 5 (E)	Light control rheostat up switch pressed	Below 1 Ω
   	Light control rheostat up switch not pressed	10 kΩ or higher
   7 (DOWN) - 5 (E)	Light control rheostat down switch pressed	Below 1 Ω
   	Light control rheostat down switch not pressed	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	Component without harness connected (Light Control Rheostat)

NG → See step   8 

OK: Go to next step 

1. Disconnect the F16 and F6 connectors.

   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
   F16-7 (RHUP) - F6-3 (UP)	Always	Below 1 Ω
   F16-7 (RHUP) - Body ground	Always	10 kΩ or higher
   F16-8 (RHDW) - F6-7 (DOWN)	Always	Below 1 Ω
   F16-8 (RHDW) - Body ground	Always	10 kΩ or higher
   F6-5 (E) - Body ground	Always	Below 1 Ω

   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   7 

1. Remove the light control rheostat.

   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
   3 (UP) - 5 (E)	Light control rheostat up switch pressed	Below 1 Ω
   	Light control rheostat up switch not pressed	10 kΩ or higher

   TEXT IN ILLUSTRATION
   
   

   *1	Component without harness connected (Light Control Rheostat)

NG → See step   8 

OK: Go to next step 

1. Disconnect the F16 and F6 connectors.

   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
   F16-7 (RHUP) - F6-3 (UP)	Always	Below 1 Ω
   F16-7 (RHUP) - 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   7