Lexus RX (RX 350L, RX450h) 2016-2025 Repair Manual: 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
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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:
|
| Interior Illumination Light2 | Door ambient illumination light | ON or OFF | Preconditions for using the Active Test to check dimmer controlled illumination:
|
| Tester Display |
|---|
| Interior Illumination Light1 |
| 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 | .gif) | PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE |
| C | | GO TO STEP 4 |
| D | | GO TO STEP 7 |
|
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| 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 |
|
| 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.
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| *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 |
|
| 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 |
|
| 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 |
|
| 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 |
|
| 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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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Owners Manual
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Lexus RX (RX 350L, RX450h) 2016-{YEAR} Repair Manual
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