Meter / Gauge System Operating Light Control Rheostat Does Not Change Light Brightness

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

SYSTEM CHECK

READ VALUE OF INTELLIGENT TESTER (RHEOSTAT VOL)

READ VALUE OF INTELLIGENT TESTER (TAIL CANCEL SW)

INSPECT LIGHT CONTROL RHEOSTAT

CHECK HARNESS AND CONNECTOR (COMBINATION METER - LIGHT CONTROL RHEOSTAT)

READ VALUE OF INTELLIGENT TESTER (TAIL CANCEL SW)

INSPECT LIGHT CONTROL RHEOSTAT

CHECK HARNESS AND CONNECTOR (COMBINATION METER - LIGHT CONTROL RHEOSTAT)

DESCRIPTION

1. The meter CPU receives signals for adjusting illumination on the meter and instrument panel from this circuit.
   
2. The meter CPU detects the illumination level selected by the user according to the position of the rheostat knob.
   

HINT:

1. This model is equipped with an Optitron meter, therefore the meter illuminates even in the daytime.
   
2. The meter illumination level can be adjusted by turning the rheostat.
   
3. The meter illumination dims when the light control switch is turned to the TAIL or HEAD position at night.
   
4. Turning the rheostat knob fully clockwise cancels the above dimmer control.
   

WIRING DIAGRAM

INSPECTION PROCEDURE

Result:

Result	Proceed to
Meter illumination does not change when operating the light control rheostat knob	A
Dimmer cancel does not operate	B

1. Connect the intelligent tester to the DLC3.
   

2. Turn the engine switch on (IG).
   

3. Turn the tester ON.
   

4. Enter the following menus: Diagnosis / Body / Combination Meter / Data List.
   

5. Check the values by referring to the table below.
   
   

   Combination Meter:

   Item	Measurement Item/Range (Display)	Normal Condition	Diagnostic Note
   Light Control Rheostat	Light control rheostat/Min.: 0, Max.: 255	Light control rheostat switch is Dark (0) → Bright (255)	-

   OK:

   The value displayed on the tester gradually changes according to the actual rheostat operation.
   

1. Connect the intelligent tester to the DLC3.
   

2. Turn the engine switch on (IG).
   

3. Turn the tester ON.
   

4. Enter the following menus: Diagnosis / Body / Combination Meter / Data List.
   

5. Check the values by referring to the table below.
   
   

   Combination Meter:

   Item	Measurement Item/Range (Display)	Normal Condition	Diagnostic Note
   Tail Cancel SW	Tail cancel switch is ON/OFF	ON: Light control rheostat is turned fully clockwise OFF: Light control rheostat position is except above	-

   OK:

   Rheostat position displayed on the tester is the same as the actual rheostat position.
   

1. Remove the light control rheostat with the connector still connected.
   

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

   Standard resistance:

   Tester Connection	Condition	Specified Condition
   E (J15-1) - RV (J15-4)	Turn the rheostat knob fully clockwise	8 to 12 kΩ
   E (J15-1) - RV (J15-4)	Rheostat knob is between MIN. and MAX.	The value changes gradually (Between approx. 0 and 8 kΩ)
   E (J15-1) - RV (J15-4)	Turn the rheostat knob fully counterclockwise	Approx. 0 Ω

1. Disconnect the J34 and J15 connectors.
   

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

1. Connect the intelligent tester to the DLC3.
   

2. Turn the engine switch on (IG).
   

3. Turn the tester ON.
   

4. Enter the following menus: Diagnosis / Body / Combination Meter / Data List.
   

5. Check the values by referring to the table below.
   
   

   Combination Meter:

   Item	Measurement Item/Range (Display)	Normal Condition	Diagnostic Note
   Tail Cancel SW	Tail cancel switch is ON/OFF	ON: Light control rheostat is turned turns fully clockwise OFF: Light control rheostat position is except above	-

   OK:

   Rheostat position displayed on the tester is the same as the actual rheostat position.
   

1. Remove the light control rheostat with the connector still connected.
   

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

   Standard resistance:

   Tester Connection	Condition	Specified Condition
   T (J15-2) - TC (J15-3)	Turn the rheostat knob fully counterclockwise	Below 1 Ω
   T (J15-2) - TC (J15-3)	Turn the rheostat knob fully clockwise	10 kΩ or higher

1. Disconnect the J34 and J15 connectors.
   

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