Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: Ambient Illumination Light Circuit

Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual / Vehicle Interior / Lighting (int) / Lighting System / Ambient Illumination Light Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the ambient illumination lights.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

  • Inspect the lights for circuits related to this system before performing the following procedure.
  • Before replacing the main body ECU (multiplex network body ECU), refer to Registration.

    Click here

PROCEDURE

1.

PERFORM ACTIVE TEST USING TECHSTREAM

(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 / Main Body / Active Test.

(e) Perform the Active Test according to the display on the Techstream.

Body Electrical > Main Body > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

Interior Illumination Light1

Instrument panel ambient illumination light

ON or OFF

Preconditions for using the Active Test to check dimmer controlled illumination:

  • Engine switch on.
  • Shift lever is in any position other than P.

Interior Illumination Light2

Door ambient illumination light

ON or OFF

Preconditions for using the Active Test to check dimmer controlled illumination:

  • Engine switch on.
  • Shift lever is in any position other than P.
Body Electrical > Main Body > Active Test

Tester Display

Interior Illumination Light1
Body Electrical > Main Body > Active Test

Tester Display

Interior Illumination Light2

OK:

Instrument panel ambient illumination light and door ambient illumination lights comes on.

Result

Proceed to

OK

A

NG (All ambient lights do not illuminate)

B

NG (Instrument panel ambient illumination light does not illuminate)

C

NG (Door ambient illumination light does not illuminate)

D
A

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

C

GO TO STEP 4

D

GO TO STEP 7

B

2.

CHECK HARNESS AND CONNECTOR (POWER SOURCE - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

(a) Disconnect the 2E instrument panel junction block assembly connector.

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

Standard Voltage:

Tester Connection

Condition

Specified Condition

2E-1 - Body ground

Always

11 to 14 V
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

3.

INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

(a) Disconnect the 2B instrument panel junction block assembly connector.

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

*a

Component without harness connected

(Instrument Panel Junction Block Assembly)

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

2E-1 - 2B-24

Always

Below 1 Ω

2E-1 - 2B-25

Always

Below 1 Ω

2E-1 - 2B-27

Always

Below 1 Ω
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

4.

INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

(a) Disconnect the 2B and 2E instrument panel junction block assembly connector.

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

*a

Component without harness connected

(Instrument Panel Junction Block Assembly)

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

2E-1 - 2B-24

Always

Below 1 Ω
NG

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

OK

5.

CHECK HARNESS AND CONNECTOR (INTERIOR ILLUMINATION LIGHT SUB-ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

(a) Disconnect the K10 interior illumination light sub-assembly connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

K10-2 - 2B-24

Always

Below 1 Ω

K10-2 or 2B-24 - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

6.

CHECK HARNESS AND CONNECTOR (INTERIOR ILLUMINATION LIGHT SUB-ASSEMBLY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))

(a) Disconnect the J9 main body ECU (multiplex network body ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

K10-1 - J9-21 (LED1)

Always

Below 1 Ω

K10-1 or J9-21 (LED1) - Body ground

Always

10 kΩ or higher
OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

7.

INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

(a) Disconnect the 2B and 2E instrument panel junction block assembly connector.

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

*a

Component without harness connected

(Instrument Panel Junction Block Assembly)

-

-

Standard Resistance:

Tester Connection

Condition

Specified Condition

2E-1 - 2B-25

Always

Below 1 Ω

2E-1 - 2B-27

Always

Always
NG

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

OK

8.

CHECK HARNESS AND CONNECTOR (DOOR TRIM BOARD SUB-ASSEMBLY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)

(a) Disconnect the M12 front door trim board sub-assembly RH connector.

(b) Disconnect the N12 front door trim board sub-assembly LH connector.

(c) Disconnect the Q5 rear door trim board sub-assembly RH connector.

(d) Disconnect the Q6 rear door trim board sub-assembly LH connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

M12-1 - 2B-27

Always

Below 1 Ω

M12-1 or 2B-27 - Body ground

Always

10 kΩ or higher

Q5-1 - 2B-27

Always

Below 1 Ω

Q5-1 or 2B-27 - Body ground

Always

10 kΩ or higher

N12-1 - 2B-25

Always

Below 1 Ω

N12-1 or 2B-25 - Body ground

Always

10 kΩ or higher

Q6-1 - 2B-25

Always

Below 1 Ω

Q6-1 or 2B-25 - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

9.

CHECK HARNESS AND CONNECTOR (DOOR TRIM BOARD SUB-ASSEMBLY - MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU))

(a) Disconnect the J9 main body ECU (multiplex network body ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

M12-2 - J9-22 (LED2)

Always

Below 1 Ω

M12-2 or J9-22 (LED2) - Body ground

Always

10 kΩ or higher

Q5-2 - J9-22 (LED2)

Always

Below 1 Ω

Q5-2 or J9-22 (LED2) - Body ground

Always

10 kΩ or higher

N12-2 - J9-22 (LED2)

Always

Below 1 Ω

N12-2 or J9-22 (LED2) - Body ground

Always

10 kΩ or higher

Q6-2 - J9-22 (LED2)

Always

Below 1 Ω

Q6-2 or J9-22 (LED2) - Body ground

Always

10 kΩ or higher
OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
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