Lexus TechDoc

LIGHTING SYSTEM > Door Courtesy Switch Circuit

for Preparation Click here

DESCRIPTION

The main body ECU (multiplex network body ECU) detects the condition of each door courtesy light switch.

WIRING DIAGRAM

INSPECTION PROCEDURE

1.READ VALUE USING INTELLIGENT TESTER

Connect the intelligent tester to the DLC3.

Turn the power switch on (IG).

Turn the intelligent tester on.

Enter the following menus: Body / Main Body / Data List.

Read the display on the intelligent tester.

Main Body
Tester Display
Measurement Item/Range
Normal Condition
Diagnostic Note
RR Door Courtesy SW
Rear door courtesy light switch RH signal/ON or OFF
ON: Rear door RH open
OFF: Rear door RH closed
-
RL Door Courtesy SW
Rear door courtesy light switch LH signal/ON or OFF
ON: Rear door LH open
OFF: Rear door LH closed
-
Back Door Courtesy SW
Back door courtesy light switch signal/ON or OFF
ON: Back door open
OFF: Back door closed
-
FR Door Courtesy
Front door RH condition signal/ON or OFF
ON: Front door RH closed
OFF: Front door RH open
-
FL Door Courtesy
Front door LH condition signal/ON or OFF
ON: Front door LH closed
OFF: Front door LH open
-

Main Body
Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
RR Door Courtesy SW	Rear door courtesy light switch RH signal/ON or OFF	ON: Rear door RH open OFF: Rear door RH closed	-
RL Door Courtesy SW	Rear door courtesy light switch LH signal/ON or OFF	ON: Rear door LH open OFF: Rear door LH closed	-
Back Door Courtesy SW	Back door courtesy light switch signal/ON or OFF	ON: Back door open OFF: Back door closed	-
FR Door Courtesy	Front door RH condition signal/ON or OFF	ON: Front door RH closed OFF: Front door RH open	-
FL Door Courtesy	Front door LH condition signal/ON or OFF	ON: Front door LH closed OFF: Front door LH open	-

OK:: Normal conditions listed above are displayed.

Result:

Result	Proceed to
OK	A
Front door courtesy light switch LH or RH does not operate	B
Rear door courtesy light switch LH or RH does not operate	C
Back door courtesy light switch does not operate	D

Go to step 2

Go to step 5

Go to step 7

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE (Click here)

2.INSPECT FRONT DOOR COURTESY LIGHT SWITCH ASSEMBLY (LH OR RH)

Disconnect the front door courtesy light switch assembly connector.

Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
Switch Condition
Specified Condition
1 - Body ground
Pushed
10 kΩ or higher
1 - Body ground
Not pushed
Below 1 Ω
Text in Illustration
*a
Component without harness connected
(Front Door Courtesy Light Switch Assembly)

Text in Illustration
*a	Component without harness connected (Front Door Courtesy Light Switch Assembly)

REPLACE FRONT DOOR COURTESY LIGHT SWITCH ASSEMBLY (Click here)

OK

3.CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY - SWITCH)

for Front LH
1. Disconnect the 2D instrument panel junction block assembly connector.
2. Disconnect the P5 front door courtesy light switch assembly LH connector.
3. Measure the resistance according to the value(s) in the table below.
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  P5-1 - 2D-35
  Always
  Below 1 Ω
  P5-1 - Body ground
  Always
  10 kΩ or higher

for Front RH
1. Disconnect the 2D instrument panel junction block assembly connector.
2. Disconnect the Q3 front door courtesy light switch assembly RH connector.
3. Measure the resistance according to the value(s) in the table below.
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  Q3-1 - 2D-36
  Always
  Below 1 Ω
  Q3-1 - Body ground
  Always
  10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

4.INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

for Front LH
1. Remove the instrument panel junction block assembly (Click here).
2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
3. Measure the resistance according to the value(s) in the table below.
  
  Text in Illustration
  *a
  Component without harness connected
  (Instrument Panel Junction Block Assembly)
  *b
  Component without harness connected
  (Instrument Panel Junction Block Assembly)
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  2D-35 - A-2 (FLCY)
  Always
  Below 1 Ω
  2D-35 - Body ground
  Always
  10 kΩ or higher

Text in Illustration
*a	Component without harness connected (Instrument Panel Junction Block Assembly)	*b	Component without harness connected (Instrument Panel Junction Block Assembly)

for Front RH
1. Remove the instrument panel junction block assembly (Click here).
2. Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.
3. Measure the resistance according to the value(s) in the table below.
  
  Text in Illustration
  *a
  Component without harness connected
  (Instrument Panel Junction Block Assembly)
  *b
  Component without harness connected
  (Instrument Panel Junction Block Assembly)
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  2D-36 - A-4 (FRCY)
  Always
  Below 1 Ω
  2D-36 - Body ground
  Always
  10 kΩ or higher

Text in Illustration
*a	Component without harness connected (Instrument Panel Junction Block Assembly)	*b	Component without harness connected (Instrument Panel Junction Block Assembly)

REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY (Click here)

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) (Click here)

5.INSPECT REAR DOOR COURTESY LIGHT SWITCH ASSEMBLY (LH OR RH)

Disconnect the rear door courtesy light switch assembly connector.

Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
Switch Condition
Specified Condition
1 - Body ground
Pushed
10 kΩ or higher
1 - Body ground
Not pushed
Below 1 Ω
Text in Illustration
*a
Component without harness connected
(Rear Door Courtesy Light Switch Assembly)

Text in Illustration
*a	Component without harness connected (Rear Door Courtesy Light Switch Assembly)

REPLACE REAR DOOR COURTESY LIGHT SWITCH ASSEMBLY (Click here)

OK

6.CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - REAR COURTESY LIGHT SWITCH)

for Rear LH
1. Disconnect the H18 main body ECU (multiplex network body ECU) connector.
2. Disconnect the P12 rear door courtesy light switch assembly LH connector.
3. Measure the resistance according to the value(s) in the table below.
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  P12-1 - H18-3 (LCTY)
  Always
  Below 1 Ω
  P12-1 - Body ground
  Always
  10 kΩ or higher

for Rear RH
1. Disconnect the H16 main body ECU (multiplex network body ECU) connector.
2. Disconnect the Q7 rear door courtesy light switch assembly RH connector.
3. Measure the resistance according to the value(s) in the table below.
  Standard Resistance:
  Tester Connection
  Condition
  Specified Condition
  Q7-1 - H16-6 (RCTY)
  Always
  Below 1 Ω
  Q7-1 - Body ground
  Always
  10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) (Click here)

7.INSPECT BACK DOOR LOCK ASSEMBLY

Remove the back door lock assembly (Click here).

Check the operation of the door lock motor.
1. Move the door lock to the lock position.
2. Apply auxiliary battery voltage to the door lock motor and check the operation of the door lock motor.
  OK:
  Connection
  Result
  Auxiliary battery positive (+) → Terminal 4 (ACT+)
  Auxiliary battery negative (-) → Terminal 3 (ACT-)
  Unlocks

Check the operation of the door courtesy switch.
1. Measure the resistance according to the value(s) in the table below.
  Standard Resistance:
  Tester Connection
  Switch Condition
  Specified Condition
  1 (E) - 2 (+)
  Locked
  10 kΩ or higher
  1 (E) - 2 (+)
  Unlocked
  Below 1 Ω
  Text in Illustration
  *a
  Component without harness connected
  (Back Door Lock Assembly)
  *b
  Lock
  *c
  Unlock

REPLACE BACK DOOR LOCK ASSEMBLY (Click here)

OK

8.CHECK HARNESS AND CONNECTOR (BACK DOOR LOCK - MAIN BODY ECU)

Disconnect the H16 main body ECU (multiplex network body ECU) connector.

Disconnect the Q17 back door lock assembly connector.

Measure the resistance according to the value(s) in the table below.
Standard Resistance:
Tester Connection
Condition
Specified Condition
Q17-2 (+) - H16-19 (BCTY)
Always
Below 1 Ω
Q17-2 (+) - Body ground
Always
10 kΩ or higher
Q17-1 (E) - Body ground
Always
Below 1 Ω

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) (Click here)

Tester Connection	Switch Condition	Specified Condition
1 - Body ground	Pushed	10 kΩ or higher
1 - Body ground	Not pushed	Below 1 Ω

Tester Connection	Condition	Specified Condition
P5-1 - 2D-35	Always	Below 1 Ω
P5-1 - Body ground	Always	10 kΩ or higher

Connection	Result
Auxiliary battery positive (+) → Terminal 4 (ACT+) Auxiliary battery negative (-) → Terminal 3 (ACT-)	Unlocks

*a	Component without harness connected (Back Door Lock Assembly)
*b	Lock
*c	Unlock