Mitsubishi Galant (2004+). Manual - part 309

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-427

INTERIOR LIGHT

GENERAL DESCRIPTION CONCERNING THE INTERIOR LIGHT

M1549021800106

The following ECUs affect the functions and control 
of the interior lights.

Interior light control function

The ETACS-ECU controls the interior lights by turn-
ing them on and off in the following way:

• When a door is opened with the ignition switch 

off, the interior lights up to a luminance of 100 
percent. When a door is closed, the interior lights 
dims at a luminance of 65 percent, and goes off 
30 seconds later. However if the ignition switch is 
turned ON or if a door is locked while the interior 
lights is dimming, the dome light will go off at that 
point.

• When a door is opened with the ignition switch 

ON, the interior lights up at a luminance of 100 
percent. When a door is closed, the interior lights 
go off.

• When the ignition key is removed with all doors 

closed, the interior lights up at a luminance of 100 
percent, and goes off 30 seconds later. However 
if the ignition key is inserted again or if a door is 
locked while the interior lights is lighting, the inte-
rior lights will go off at that point.

• To check keyless entry operations more easily, 

the interior lights is flashed once when the doors 
are locked. When the doors are unlocked, the 
interior lights at a luminance of 100 percent, and 
go off 15 seconds later.

NOTE: The dimmer function can be customized on 
vehicles equipped with a multi center display (middle 
grade type).  Refer to 

P.54B-578

.

NOTE: The dotted lines indicate that lighting mode 
when the ignition switch is turned ON, door is locked, 
or any door is opened during the timer illumination 
time.

FUNCTION

CONTROL ECU

Interior light control function

ETACS-ECU

Interior light automatic-shutoff function

ETACS-ECU

Ignition key hole illumination light function

ETACS-ECU

Door ajar indicator

ETACS-ECU

Seat belt indicator

ETACS-ECU

AC101555AF

ON

ACC

LOCK (OFF)

Key removed

ON (Any door is open)

OFF (All doors are closed)

LOCK

OFF

UNLOCK

100 %

65 %

0 %

t1: 30 seconds
t2: 15 seconds

t1

t1

t2

Ignition switch

Door switch

Keyless entry sytem
door lock or unlock signal

Interior light intensity

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-428

Interior light automatic-shutoff function

Illuminated interior lights such as the front dome 
light, etc. (all lights using the dome light fuse as the 
power supply) will automatically go off in the follow-
ing conditions to prevent the battery from discharging 
as a result of forgetting to turn off the lights or incom-
plete closing of the door.

• When the ignition switch is turned off and more 

than 30 minutes pass with the interior light illumi-
nated, the interior lights will go off automatically.

• When the ignition switch is turned off and one of 

the door switches remains open for 30 minutes 
continuously, the interior lights will go off auto-
matically.

NOTE: The interior light automatic shutoff function 
can be customized on vehicles equipped with a multi 
center display (middle grade type).  Refer to 

P.54B-578

.

Ignition key hole illumination light function
The ignition key hole illumination light illuminates when the 
driver's door is opened with the ignition switch off, and for 30 
seconds after the driver's door is closed. It also illuminates for 
30 seconds after the ignition key is pulled out. In any case, it 
goes out when the ignition switch is turned on.
Door ajar indicator
The combination meter receives the signal sent from the 
ETACS-ECU about whether each door is open or closed and 
turns the door ajar indicator on and off. While the door ajar indi-
cator is illuminated, the door ajar warning function is activated 
and the door ajar indicator flashes 4 times. If the door remains 
open even after the 4 warning flashes, the door ajar indicator 
will be illuminated again. And when the interior light auto-
matic-shutoff function is activated, the door ajar indicator is 
extinguished.

AC210856 AB

T1

T2

T2

ON

ON (Any door is open)

Illuminated

ACC

OFF

Extinguished

Ignition switch

Door switch

Interior light

ON

DOOR

Dome light switch

T1: 30 minutes
T2: Within 30 minutes

T1

T2

OFF (All doors are closed)

T1

SYMPTOM PROCEDURES

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-429

Seat belt indicator

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).

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

TSB Revision

SIMPLIFIED WIRING SYSTEM (SWS)

54B-430

• 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. 

General circuit diagram for interior lights