Lexus NX: Interior Light Switch Signal Circuit

Lexus NX Service Manual / Vehicle Interior / Lighting (int) / Lighting System / Interior Light Switch Signal Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) detects the condition of the door switch and front dome light switch.

WIRING DIAGRAM

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CAUTION / NOTICE / HINT

NOTICE:

  • Recognition code registration is necessary when replacing the main body ECU (multiplex network body ECU).
  • If the main body ECU (multiplex network body ECU) is replaced, refer to Registration.

PROCEDURE

1.

READ VALUE USING TECHSTREAM (DOME LIGHT DOOR SW, DOME LIGHT SW)

(a) Using the Techstream, read the Data List.

Click here

Body Electrical > Main Body > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Dome Light DOOR SW

Door switch signal

ON or OFF

ON: Door switch on

OFF: Door switch off

-

Dome Light SW

Front dome light switch signal

ON or OFF

ON: Front dome light switch on

OFF: Front dome light switch off

-

Body Electrical > Main Body > Data List

Tester Display

Dome Light DOOR SW

Dome Light SW

OK:

Normal conditions listed above are displayed.

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

2.

INSPECT MAP LIGHT ASSEMBLY

(a) Remove the map light assembly.

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(b) Inspect the map light assembly.

Click here

NG

REPLACE MAP LIGHT ASSEMBLY

OK

3.

CHECK HARNESS AND CONNECTOR (MAP LIGHT ASSEMBLY - MAIN BODY ECU)

(a) Disconnect the T6 and T7 map light assembly connectors.

(b) Disconnect the I47 main body ECU (multiplex network body ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

T7-18 (DOOR) - I47-27 (DMDR)

Always

Below 1 Ω

T7-19 (CILL) - I47-28 (DMON)

Always

Below 1 Ω

T7-20 (GND9) - Body ground

Always

10 kΩ or higher

T7-18 (DOOR) or I47-27 (DMDR) - Body ground

Always

10 kΩ or higher

T7-19 (CILL) or I47-28 (DMON) - 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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