Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Operating Light Control Rheostat does not Change Light Brightness

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Vehicle Interior / Meter / Gauge / Display / Meter / Gauge System / Operating Light Control Rheostat does not Change Light Brightness

DESCRIPTION

The combination meter assembly receives signals from this circuit to adjust the illumination of the combination meter assembly. The combination meter assembly sets the illumination level based on the user operation of the light control rheostat switch in the trip switch.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When replacing the combination meter assembly, always replace it with a new one. If a combination meter assembly which was installed to another vehicle is used, the information stored in it will not match the information from the vehicle and a DTC may be stored.

HINT:

  • The meter illumination level can be adjusted by pressing the light control rheostat switch.
  • The meter illumination dims when the taillights are turned on.
  • Setting the meter illumination level to maximum brightness cancels the above dimming of the meter illumination.

PROCEDURE

1.

READ VALUE USING TECHSTREAM (LIGHT CONTROL UP SWITCH, LIGHT CONTROL DOWN SWITCH)

(a) Connect the Techstream to the DLC3.

(b) Turn the engine switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Combination Meter / Data List.

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Combination Meter > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Light Control Up Switch

Light control rheostat up switch

OFF or ON

OFF: Switch released

ON: Switch pressed

-

Light Control Down Switch

Light control rheostat down switch

OFF or ON

OFF: Switch released

ON: Switch pressed

-

Body Electrical > Combination Meter > Data List

Tester Display

Light Control Up Switch

Light Control Down Switch

OK:

Light control rheostat up or down switch condition displayed on the Techstream changes with the actual switch operation.

OK

REPLACE COMBINATION METER ASSEMBLY

NG

2.

INSPECT TRIP SWITCH

(a) Remove the trip switch.

Click here

(b) Inspect the trip switch.

Click here

NG

REPLACE TRIP SWITCH

OK

3.

CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - TRIP SWITCH)

(a) Disconnect the J10 combination meter assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

J10-25 (TR) - J1-5 (RV)

Always

Below 1 Ω

J10-26 (SW3) - J1-7 (E)

Always

Below 1 Ω

J10-25 (TR) or J1-5 (RV) - Body ground

Always

10 kΩ or higher

J10-26 (SW3) or J1-7 (E) - Body ground

Always

10 kΩ or higher

OK

REPLACE COMBINATION METER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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