Mitsubishi Galant (2004+). Manual - part 1687

ECU FUNCTIONS AND CONTROLS IN THE SWS

SIMPLIFIED WIRING SYSTEM (SWS)

54B-19

Mist wiper control

When the ignition switch is in the ACC or ON posi-
tion, and the windshield mist wiper switch of the col-
umn switch is turned ON, the front-ECU turns ON the 
windshield wiper drive signal. At the same time, the 
wiper speed switching relay is turned ON 
(HIGH-SPEED). While the windshield mist wiper 
switch is ON, the windshield wiper will operate at 
high speed. Then, if the windshield mist wiper switch 
is turned off, the wiper operates at low speed until it 
stops at the predetermined park position.

When the windshield mist switch is turned on briefly, 
the wiper operates once at low speed.
At the point the windshield mist switch is turned ON, 
if the windshield wiper has been operating intermit-
tently, the same operations as the above will be per-
formed while the windshield mist wiper switch is ON. 
After the windshield mist wiper switch goes OFF, the 
intermittent operations will be set again T1 seconds 
after the last windshield wiper auto-stop signal turn-
ing ON.

.

Low speed wiper, high speed wiper control

When the ignition switch in at the ACC or ON posi-
tion, and the windshield low speed wiper switch of 
the column switch is turned ON, the front-ECU turns 
ON the windshield wiper drive signal, turns OFF (LO) 
the windshield wiper speed relay, and operates the 

windshield wiper at low speed. Next, when the wind-
shield high speed wiper switch is turned ON, the 
windshield wiper drive signal is turned ON, the wind-
shield wiper speed switching relay is turned ON (HI), 
and the windshield wiper is operated at high speed.

.

AC200047AB

ON

OFF

ON

OFF

ON

OFF

ON (HIGH)

Windshield mist wiper switch

Windshield wiper auto-stop 
signal

Windshield wiper drive signal

Windshield wiper speed 
switching relay

OFF (LOW)

When windshield 
wiper switch is OFF

When windshield intermittent 
wiper is operating

T1: Intermittent time

T1

T1

AC005437AF

ON

OFF

ON

OFF

ON

OFF

ON (HIGH)

Windshield low-speed 
wiper switch

Windshield high-speed 
wiper switch

Windshield wiper auto-stop 
signal

ON

OFF

Windshield wiper 
drive signal

Windshield wiper 
speed switching relay OFF (LOW)

Low speed operations

High speed operations

ECU FUNCTIONS AND CONTROLS IN THE SWS

SIMPLIFIED WIRING SYSTEM (SWS)

54B-20

Washer control

When the ignition switch is in the ACC or ON posi-
tion, and the windshield washer switch of the column 
switch is turned ON, the front-ECU turns ON the 
windshield washer relay. The windshield wiper drive 
signal is turned ON after 0.15 seconds until 2 sec-
onds after the windshield washer switch goes OFF to 

operate the windshield wiper continuously. When the 
windshield washer switch is turned ON, if the wind-
shield wiper is operating intermittently, intermittent 
operations will be continued after continuous opera-
tions.
NOTE: The wiper drive signal output time varies 
according to the conditions. Refer to the following 
table for details.

AC306460 AB

ON

OFF

ON

OFF

ON

OFF

ON

WINDSHIELD WASHER 
SWITCH

WINDSHIELD WASHER 
RELAY

WINDSHIELD WIPER 
AUTO-STOP SIGNAL

WINDSHIELD WIPER 
DRIVE SIGNAL

OFF

WHEN WINDSHIELD WIPER 
SWITCH IS OFF

WHEN WINDSHIELD INTERMITTENT 
WIPER IS OPERATING

T: WIPER OPERATING TIME AFTER WINDSHIELD WASHER SWITCH IS OFF

TI

TI

TI

T

T

t1

t1

t2

t2

t2: WINDSHIELD WASHER OPERATING TIME

t1: 0.15 SECONDS

TI: INTERMITTENT TIME

WHEN WIPER SWITCH IS OFF WHEN WIPER SWITCH IS SET 

TO INT

WHEN WIPER SWITCH IS SET 
TO LO OR HI

t2 0.15 

second or 
less

0.15 - 0.8 
second

0.8 
second or 
more

0.15 
second or 
less

0.15 - 0.8 
second

0.8 
second or 
more

0.15 
second or 
less

0.15 - 0.8 
second

0.8 
second or 
more

T

0 second 1.2 

seconds

2 seconds 0 second 1.2 

seconds

2 seconds 0 second 1.2 

seconds

2 seconds

ECU FUNCTIONS AND CONTROLS IN THE SWS

SIMPLIFIED WIRING SYSTEM (SWS)

54B-21

HEADLIGHTS AND TAILLIGHTS

.

Taillights
If the column switch sends a taillight switch "ON" signal to the 
front-ECU, the front-ECU turns on its taillight relay, causing the 
taillights to illuminate.
NOTE: This description covers the taillights only. In actual driv-
ing, the taillights may be turned off due to the headlight auto-
matic shut-off function. For the details of the headlight 
automatic shut-off function, refer to the Section.

.

Headlights

If the column switch sends a headlight switch "ON" 
signal to the front-ECU, the front-ECU turns on its 
headlight relay (LOW), causing the low-beam head-
lights to illuminate. If the dimmer switch is turned on 
while the headlight relay (LOW) is on, the front-ECU 
turns on the headlight relay (HIGH), causing the 
high-beam headlights to illuminate.

NOTE: This description covers the headlights only. In 
actual driving, the headlights may be turned off due 
to the headlight automatic shut-off function. For the 
details of the headlight automatic shut-off function, 
refer to its Section.

.

AC106502

ON

OFF

ON

OFF

Taillight
switch

Taillight
relay

AB

AC306461

Headlight switch

ON

OFF

Headlight (Low)

ON

OFF

ON

OFF

Headlight 
relay (High)

ON

OFF

High-beam 
indicator light

ON

OFF

Front ECU
acknowdge

Hi-beam

ACK

OTHERS

Passing/Dimmer
switch

ON

PASS

OFF

AB

<2-bulb type>

<4-bulb type>

ECU FUNCTIONS AND CONTROLS IN THE SWS

SIMPLIFIED WIRING SYSTEM (SWS)

54B-22

Headlight automatic-shutoff function
Even if the lighting switch (taillights switch or headlight switch) 
is ON, the headlight (including the taillights) will automatically 
go off in the following conditions to prevent the battery from dis-
charging as a result of forgetting to turn off lights.
When the ignition key is turned from "ON" to "LOCK" (OFF) or 
"ACC" position with the lighting switch turned ON, and this 
state continues for three minutes, the light will automatically be 
turned off. If the driver's seat door is opened during these three 
minutes, the light will go off one second later.
NOTE: The headlight automatic-shutoff function can be cus-
tomized on vehicles equipped with a multi center display (mid-
dle grade type.) Refer to 

P.54B-28

.

.

High-beam indicator
At the same time that the high-beams are illuminated, the 
ETACS-ECU sends a signal to illuminate the high beam indica-
tor via the CAN bus line. The combination meter receives the 
transmitted signal and turns the high-beam indicator on and off.

.

Daytime running light function

The front-ECU illuminates the low-beam headlights 
at a reduced brightness when the ignition switch is 
turned "ON" with the headlight switch is at the "OFF" 
or "TAIL" position. It illuminates the low-beam head-
lights at a normal brightness when the headlights are 
turned on with the daytime running lights on.

AC101466AB

T1: 3 minutes
T2: 1 second

ON

ON

ON

OFF

OFF

OFF

Ignition switch 
(IG1)

Driver's door 
switch

Taillight switch or 
headlight switch

Illumination 
output signal

ON

OFF

T1

T2

AC201190

Passing / Dimmer
switch

Headlight
switch

ON

OFF

HEAD

OFF or TAIL

Ignition switch
(IG2)

ON

OFF

Headlight

High-beam

Low-beam

(Normal)

Low-beam

(Dim)

OFF

AC