Mitsubishi 380. Manual - part 90

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-357

Seat belt indicator

AC305420

ON

OFF

ON (UNFASTENED)

OFF (FASTENED)

ON (ILLUMINATED)

OFF (NOT ILLUMINATED)

IGNITION SWITCH (IG1)

SEAT BELT  

SWITCH

(DRIVER'S SIDE)

SEAT BELT 

WARNING

LIGHT

AC

AC305443

ON

OFF

ON (UNFASTENED)

OFF (FASTENED)

ON (ILLUMINATED)

OFF (NOT ILLUMINATED)

IGNITION SWITCH (IG1)

SEAT BELT 

SWITCH

(DRIVER'S SIDE)

SEAT BELT 

WARNING

LIGHT

8 km/h (5 mph)

0 km/h (0 mph)

VEHICLE SPEED

e

3 km/h (2 mph)

ON

OFF

a: 0.48 SECOND

b: 0.52 SECOND

c: 1 SECOND

d: 3 SECONDS

e: 60 SECONDS  OR MORE

f: 10 SECONDS

AB

a

g

g

g

f

b

c

c

c

c

c

d

12 CYCLES

1 CYCLE

12 CYCLES

12 CYCLES

12 CYCLES

SEAT BELT 

WARNING

LIGHT

g: 0.5 SECOND

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-358

If any of the following conditions is met with the igni-
tion switch at "ON" or "ST", the ETACS-ECU illumi-
nates, flashes or extinguishes the seat belt indicator 
by using the driver's seat belt switch signal and the 
vehicle speed signal sent from the combination 
meter.

• Illuminates when the ignition switch is at "ON" 

and the seat belt switch is turned on (the driver's 
seat belt is unfastened).

• Flashes and illuminates the indicator 12 cycles 

(after 0.5 seconds) if any of the following condi-
tions is met when sixty seconds or more have 
elapsed since the ignition switch is turned "ON". 
One cycle consists of five-second "flashing" and 
then three-second "illumination".

a. The vehicle speed has reached 8 km/h (5 

mph) while the seat belt switch is turned on 
(driver's seat belt is not fastened) with the 
ignition switch "ON.

b. The seat belt switch has been turned on 

(driver's seat belt has not been fastened) for 
at least ten seconds while the ignition switch 
has been turned "ON" and the vehicle speed 
has been 8 km/h (5 mph) or more.

NOTE: Once this timer operation has been acti-

vated, it will not be activated again until the 
vehicle speed reduces to 3 km/h (2 mph) or 
less even if any of the following conditions is 
met.

• The indicator stops illuminating if the ignition 

switch or the seat belt switch is turned off (the 
driver's seat belt is fastened) while the timer 
operation is active. 

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

16DB327A

CONNECTOR: C-219

JUNCTION BLOCK

(REAR VIEW)

16DB453A

CONNECTORS: D-02, D-03

D-02

D-03

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-360

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

• MB991813: SWS Monitor Kit

• MB991806: SWS Monitor Cartridge

• MB991812: SWS Monitor Harness (For Column-ECU)

• MB991822: Test Probe Harness