METER / GAUGE SYSTEM > Operating Light Control Rheostat does not Change Light Brightness

for Preparation Click here


DESCRIPTION

The meter ECU receives signals from this circuit to adjust the illumination of the meter. The meter ECU sets the illumination level based on the user operation of the light control rheostat.

HINT:
  1. The meter illumination level can be adjusted by operating the light control rheostat.
  1. The meter illumination dims when the light control switch is turned to the tail, head, or AUTO position at night.
  1. Setting the meter illumination to maximum brightness cancels the above dimming of the meter illumination.


WIRING DIAGRAM


E163225E11


INSPECTION PROCEDURE

1.SYSTEM CHECK

  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
Go to step 6
A


2.READ VALUE USING INTELLIGENT TESTER (RHEOSTAT VALUE)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the intelligent tester on.

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

  1. 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 intelligent tester gradually changes as the actual rheostat knob operation.



NG
Go to step 4
OK


3.READ VALUE USING INTELLIGENT TESTER (TAIL CANCEL SW)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the intelligent tester on.

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

  1. 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 intelligent tester is the same as the actual light control rheostat knob position.



NG
Go to step 7
OK

REPLACE COMBINATION METER ASSEMBLY (Click here)  

4.INSPECT LIGHT CONTROL RHEOSTAT


    E184972E05

  1. Remove the light control rheostat (Click here).

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

    Standard Resistance:
    Tester Connection
    		Switch Condition
    		Specified Condition
    1 (E) - 3 (RV)
    		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 
    *a
    		Component without harness connected
    (Light Control Rheostat)



NG
REPLACE LIGHT CONTROL RHEOSTAT (Click here)
OK


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

  1. Disconnect the H19 and H40 connectors.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    H19-14 (REV) - H40-3 (RV)
    		Always
    		Below 1 Ω
    H19-14 (REV) - Body ground
    		Always
    		10 kΩ or higher
    H19-36 (SW3) - H40-1 (E)
    		Always
    		Below 1 Ω
    H19-36 (SW3) - Body ground
    		Always
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE COMBINATION METER ASSEMBLY (Click here)  

6.READ VALUE USING INTELLIGENT TESTER (TAIL CANCEL SW)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the power switch on (IG).

  1. Turn the intelligent tester on.

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

  1. 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 intelligent tester is the same as the actual light control rheostat knob position.



NG
Go to step 7
OK

REPLACE COMBINATION METER ASSEMBLY (Click here)  

7.INSPECT LIGHT CONTROL RHEOSTAT


    E184972E06

  1. Remove the light control rheostat (Click here).

  1. 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 
    *a
    		Component without harness connected
    (Light Control Rheostat)



NG
REPLACE LIGHT CONTROL RHEOSTAT (Click here)
OK


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

  1. Disconnect the H19 and H40 connectors.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    H19-16 (SW1) - H40-7 (T)
    		Always
    		Below 1 Ω
    H19-16 (SW1) - Body ground
    		Always
    		10 kΩ or higher
    H19-15 (TC) - H40-5 (TC)
    		Always
    		Below 1 Ω
    H19-15 (TC) - Body ground
    		Always
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE COMBINATION METER ASSEMBLY (Click here)