Operating Light Control Rheostat Does Not Change Light Brightness

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

DESCRIPTION

The combination meter assembly controls the combination meter illumination in accordance with the light control signal from the light control rheostat.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM (RHEOSTAT)

(a) Connect a Techstream to the DLC3.

(b) Turn the ignition switch on and the tester on.

(c) Operate the Techstream according to the display and select "Data List" Meter / Gauge System.

Body Electrical / Combination Meter / Data List::





OK:

Light brightness can be changed within the specified range by actual operation.

NG -- INSPECT FUSE (PANEL1)

OK -- REPLACE COMBINATION METER ASSEMBLY Removal

2. INSPECT FUSE (PANEL1)

(a) Remove the PANEL1 fuse from the main body ECU.





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

Standard resistance:





(c) Reinstall the PANEL1 fuse.

NG -- REPLACE FUSE
OK -- Continue to next step.

3. CHECK HARNESS AND CONNECTOR (PANEL1 FUSE - LIGHT CONTROL RHEOSTAT)

(a) Disconnect the F28 light control rheostat connector.





(b) Measure the voltage according to the value in the table below.

Standard voltage:





(c) Reconnect the light control rheostat connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

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

(a) Disconnect the F2 combination meter assembly connector.





(b) Disconnect the F28 light control rheostat connector.

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

Standard resistance:





(d) Reconnect the combination meter assembly connector.

(e) Reconnect the light control rheostat connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

5. INSPECT LIGHT CONTROL RHEOSTAT

(a) Remove the light control rheostat but without disconnecting the connector.





(b) Turn the ignition switch on.

(c) Using an oscilloscope, check the signal waveform of the light control rheostat.





OK:

Waveform is as shown in the illustration.

HINT
Duty ratio changes as the illumination dims. (A becomes longer)

(d) Reinstall the light control rheostat.

NG -- REPLACE LIGHT CONTROL RHEOSTAT

OK -- REPLACE COMBINATION METER ASSEMBLY Removal