Mitsubishi Galant 9G. Manual - part 92

SYMPTOM PROCEDURES

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SIMPLIFIED WIRING SYSTEM (SWS)

54B-364

STEP 2. Check the input signal by using "DATA LIST" 
menu of the SWS monitor.
Check the input signals from the following switches:

• Ignition switch: "ON" to "OFF"

• Lighting switch: "TAIL" or "HEAD"

CAUTION

To prevent damage to scan tool MB991958, always turn the 
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958. Connect 
special tool MB991910 before connecting special tool 
MB991812. Be sure to connect special tool MB991806 after 
turning on special tool MB991824.
(1) Connect the special tool. Refer to "How to connect SWS 

monitor 

P.54B-13

."

(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3) Operate scan tool MB991958 according to the procedure 

below to display "H/L AUTO-CUT."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "LIGHTING."
g. Select "H/L AUTO-CUT."

(4) Check that normal conditions are displayed for the items 

described in the table below.

(5) When the driver's door is opened, check that normal 

conditions are displayed for the items described in the table 
below.

Q: Does the scan tool MB991958 display the items 

"TAILLIGHT SW", "IG SW IG1", "FRONT DOOR SW" and 
"H/L AUTO-CUT" as normal condition?
Normal conditions are displayed for all the items : 

Replace the front-ECU. Verify that the headlight 
automatic shutdown function works normally.

Normal condition is not displayed for "TAILLIGHT SW" : 

Refer to Inspection Procedure M-5 "ETACS-ECU 
does not receive any signal from the taillight switch 

P.54B-484

."

Normal condition is not displayed for "IG SW (IG1)" : 

Refer to Inspection Procedure M-2 "ETACS-ECU 
does not receive any signal from the ignition switch 

ITEM NO.

ITEM NAME

NORMAL CONDITION

ITEM 01

TAILLIGHT SW

ON

ITEM 30

IG SW (IG1)

OFF

ITEM NO.

ITEM NAME

NORMAL CONDITION

ITEM 32

FRONT DOOR SW ON

ITEM 35

H/L AUTO-CUT

ON

AC305411AB

MB991910

DATA LINK

CONNECTOR

MB991827

MB991824

MB991806

MB991812

AC302210

COLUMN SWITCH 
CONNECTOR

COLUMN SWITCH 
CONNECTOR AT 
HARNESS SIDE 

MB991812

AB

SYMPTOM PROCEDURES

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SIMPLIFIED WIRING SYSTEM (SWS)

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(IG1) 

P.54B-470

."

Normal condition is not displayed for "FRONT DOOR 
SW" : Refer to Inspection Procedure M-4 "ETACS-ECU 

does not receive any signal from the front door 
switches 

P.54B-477

."

Normal condition is not displayed for "H/L AUTO-CUT" : 

Replace the front-ECU. Check that the headlight 
automatic shutdown function works normally.

INSPECTION PROCEDURE H-10: Headlight and Taillight: Headlight dimmer switch automatic 
resetting function does not work normally.

.

CIRCUIT OPERATION

The headlight dimmer switch automatic resetting 
function is controlled by the front-ECU.

.

TECHNICAL DESCRIPTION (COMMENT)

If the headlight dimmer switch automatic resetting 
function does not work normally, the front-ECU may 
be defective.

.

TROUBLESHOOTING HINT

The front-ECU may be defective

DIAGNOSIS

Replace the front-ECU.
Check that the headlight dimmer switch automatic resetting 
function works normally.

· 

DIMMER

 SWITCH

· HEADLIGHT SWITCH

ETACS-
ECU

INPUT SIGNAL

Headlight (Dimmer/Passing) Input Signal

SYMPTOM PROCEDURES

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SIMPLIFIED WIRING SYSTEM (SWS)

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FLASHER TIMER

GENERAL DESCRIPTION CONCERNING THE FLASHER TIMER

M1549023600238

The following ECUs affect the functions and control 
of the flasher timer.

FLASHER TIMER FUNCTION

.

TURN-SIGNAL LIGHT

The turn-signal light output (flashing signal) is turned ON when 
the ignition switch is ON and the turn-signal light switch is ON 
(LH or RH). If the front turn-signal light or rear turn-signal light 
bulb has burned out, the flashing speed increases to indicate 
that the bulb has burned out.

.

TURN-SIGNAL INDICATORS

At the same time that the turn-signal lights are illuminated, the 
ETACS-ECU sends a signal to illuminate the turn-signal light 
indicator via the CAN bus line. The combination meter receives 
the transmitted signal and turns the turn-signal light indicator 
on and off.

.

HAZARD WARNING LIGHT

Detects the signal where the hazard warning light switch input 
changes from OFF to ON, and reverse the flashing state 
according to this signal. The hazard warning lights toggle on 
and off whenever the hazard warning light switch is operated.
NOTE: The hazard warning light switch is a push-return type 
toggle switch.

FUNCTION

CONTROL ECU

Turn-signal light

ETACS-ECU, column switch

Turn-signal indicators

ETACS-ECU, column switch

Hazard warning light

ETACS-ECU

AC005444AB

Ignition switch

Turn signal 

light switch LH

Turn signal 

light switch RH

Turn signal 

light output LH

Turn signal 

light output RH

ON

OFF

ON

OFF

ON

OFF

ON

OFF

ON

OFF

AC005445AB

Hazard light
switch

Turn signal 
light output LH

Turn signal 
light output RH

ON

OFF

ON

OFF

ON

OFF

SYMPTOM PROCEDURES

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SIMPLIFIED WIRING SYSTEM (SWS)

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General circuit diagram for the turn-signal light and hazard light

JUNCTION BLOCK

ETACS-
ECU

BATTERY

IGNITION
SWITCH (IG1)

FRONT-ECU

RELAY
BOX

HAZARD WARNING
LIGHT SWITCH 

RHEOSTAT

COLUMN
SWITCH

TURN-SIGNAL
SWITCH

COLUMN-ECU

DATA LINK
CONNECTOR

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RELAY BOX
(FUSE     )

RELAY BOX
(FUSE     )

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