Page 359 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-359
INSPECTION PROCEDURE K-1: Interior Light: The dome lamp do not illuminate and go out normally.
NOTE: This troubleshooting procedure requires the
use of diagnostic tool MB991958 and SWS monitor
kit MB991813. For details on how to use the SWS
monitor, refer to "How to connect SWS monitor
P.54B-13."
.
CIRCUIT OPERATION
The ETACS-ECU operates the dome lamp according
to the following signals:
Ignition switch (IG1): ON or OFF
Key reminder switch: ON or OFF
Door switches: ON or OFF
Driver’s door lock actuator switch: ON or OFF
Interior lamp loaded signal: ON
.
TECHNICAL DESCRIPTION (COMMENT)
If the dome lamp does not illuminate normally, a
burned-out dome lamp bulb, the input circuits from
the switches described in "CIRCUIT OPERATION",
the power supply line to the switches or the
ETACS-ECU may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
Trouble in input signal system
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The ETACS-ECU may be defective
Page 364 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-364
STEP 4. Check ETACS-ECU connector C-219 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is ETACS-ECU connector C-219 in good condition?
YES : Go to Step 5.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Verify that the dome lamp illuminates
normally.
STEP 5. Check the wiring harness between map lamp
assembly connector D-02 (terminal 1)
or overhead console assembly connector D-03 (terminal 1)
and ETACS-ECU connector C-219 (terminal
6).
Page 365 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-365
NOTE: Also check junction block connector C-205 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-205 is damaged,
repair or replace the damaged component(s) as described in
GROUP 00E, Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between map lamp assembly
connector D-02 (terminal 1) or
overhead console assembly connector D-03 (terminal 1)
and ETACS-ECU connector C-219
(terminal 6) in good condition?
YES : Replace the ETACS-ECU. Verify that the dome lamp
illuminates normally.
NO : The wiring harness may be damaged or the
connector(s) may have loose, corroded or damaged
terminals, or terminals pushed back in the connector.
Repair the wiring harness as necessary. Verify that
the dome lamp illuminates normally.
Page 366 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-366
INSPECTION PROCEDURE K-2: Interior Light: The front dome lamp, rear dome lamp or trunk lamp do
not illuminate or go out normally.
.
CIRCUIT OPERATION
The ETACS-ECU operates the dome lamp according
to the following signals:
Ignition switch (IG1): ON or OFF
Key reminder switch: ON or OFF
Door switches: ON or OFF
Trunk lid latch assembly: ON or OFF
Driver’s door lock actuator switch: LOCK or
UNLOCK
.
Page 367 of 1500
SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-367
TECHNICAL DESCRIPTION (COMMENT)
Is the dome lamp does not flash normally, a
burned-out dome lamp bulb, the input circuits from
the switches described in "CIRCUIT OPERATION",
the power supply line to the switches or the
ETACS-ECU may be defective.
.
TROUBLESHOOTING HINTS
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80
The front dome lamp bulb may be defective
The rear dome lamp bulb may be defective
The trunk lamp bulb may be defective
The wiring harness or connectors may have
loose, corroded, or damaged terminals, or termi-
nals pushed back in the connector
The ETACS-ECU may be defective
Page 368 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-368
DIAGNOSIS
Required Special Tools:
MB991223: Harness Set
MB991958: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.)
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
STEP 1. Check which of the front dome lamp, rear dome
lamp or trunk lamp do not illuminate normally.
Q: Which of the front dome lamp, rear dome lamp or trunk
lamp fail to illuminate normally?
Front dome lamp and rear dome lamp : Go to Step 2.
Front dome lamp : Go to Step 4.
Rear dome lamp : Go to Step 9.
Tru n k l am p : Go to Step 14.
STEP 2. Check map lamp assembly connector D-02
, overhead console assembly connector
D-03 and ETACS-ECU connector C-219 for
loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Is map lamp assembly connector D-02
sunroof>, overhead console assembly connector D-03
and ETACS-ECU connector C-219 in
good condition?
YES : Go to Step 3.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Check that the front dome lamp and rear
dome lamp illuminates normally.
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SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-369
STEP 3. Check the wiring harness between map lamp
assembly connector D-02 (terminals 1 and 2)
sunroof> or overhead console assembly connector D-03
(terminals 1 and 2) and ETACS-ECU
connector C-219 (terminals 6 and 5).
Q: Is the wiring harness between map lamp assembly
connector D-02 (terminals 1 and 2) or
overhead console assembly connector D-03 (terminals
1 and 2) and ETACS-ECU connector
C-219 (terminals 6 and 5) in good condition?
YES : No action is necessary and testing is complete.
NO : The wiring harness may be damaged or the
connector(s) may have loose, corroded or damaged
terminals, or terminals pushed back in the connector.
Repair the wiring harness as necessary. Check that
the front dome lamp and rear dome lamp illuminates
normally.
STEP 4. Check map lamp assembly connector D-02
or overhead console assembly
connector D-03 for loose, corroded or
damaged terminals, or terminals pushed back in the
connector.
Q: Is map lamp assembly connector D-02
sunroof> or overhead console assembly connector
D-03 in good condition?
YES : Go to Step 5.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Check that the front dome lamp illuminates
normally.
STEP 5. Check the front dome lamp bulb.
Q: Is the front dome lamp bulb in good condition?
YES : Go to Step 6.
NO : Replace the front dome lamp bulb. Check that the
front dome lamp illuminates normally.
Page 370 of 1500

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-370
STEP 6. Check the ground circuit to the front dome lamp.
Measure the resistance at map lamp assembly connector
D-02 or overhead console assembly
connector D-03 .
(1) Disconnect map lamp assembly connector D-02
sunroof> or overhead console assembly connector D-03
and measure the resistance available at the
wiring harness side of the connector.
(2) Measure the resistance value between terminal 3 and
ground.
The resistance should be 2 ohms or less.
Q: Is the measured resistance 2 ohms or less?
YES : Go to Step 8.
NO : Go to Step 7.
STEP 7. Check the wiring harness between map lamp
assembly connector D-02 (terminal 3)
or overhead console assembly connector D-03 (terminal 3)
and ground.
Q: Is the wiring harness between map lamp assembly
connector D-02 (terminal 3) or
overhead console assembly connector D-03 (terminal 3)
and ground in good condition?
YES : Replace the overhead console assembly. Check that
the front dome lamp illuminates normally.
NO : The wiring harness may be damaged or the
connector(s) may have loose, corroded or damaged
terminals, or terminals pushed back in the connector.
Repair the wiring harness as necessary. Check that
the front dome lamp illuminates normally.