Mitsubishi 380. Manual - part 86

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-341

STEP 2. Check the input signal by using "FUNCTION 
DIAG." menu of the SWS monitor.
Set each switch to the following condition before checking input 
signal from the fog lamp switch:

• Ignition switch: ON

• Fog lamp switch: ON

NOTE: Turn the ignition switch to the "ON" position in order to 
disable the headlamp automatic shutdown function.

CAUTION

To prevent damage to Diagnostic Tool MB991958, always 
turn the ignition switch to the "LOCK" (OFF) position 
before connecting or disconnecting Diagnostic Tool 
MB991958. Connect special tool MB991910 before con-
necting 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) Operate Diagnostic Tool MB991958 according to the 

procedure below to display "F.FOG."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f.

Select "LIGHTING."

g. Select "F.FOG."

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

described in the table below.

Q: Does the Diagnostic Tool MB991958 display the items 

"IG SW (IG1)" and "F.FOG LAMP" as normal condition?
Normal conditions are displayed for all the items : Go to 

Step 3.

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 
(IG1) 

P.54B-408

."

Normal condition is not displayed for "F.FOG LAMP" : 

Refer to Inspection Procedure M-3 "ETACS-ECU 
does not receive any signal from the fog lamp switch 

P.54B-410

."

ITEM NO.

ITEM NAME

NORMAL CONDITION

ITEM 30

IG SW (IG1)

ON

ITEM 36

F.FOG LAMP

ON

00DB076A

MB991910

DATA LINK

CONNECTOR

MB991824

MB991827

AC302210

COLUMN SWITCH 
CONNECTOR

COLUMN SWITCH 
CONNECTOR AT 
HARNESS SIDE 

MB991812

AB

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-342

STEP 3. Check fog lamp relay connector A-05X for loose, 
corroded or damaged terminals, or terminals pushed back 
in the connector.
Q: Is fog lamp relay connector A-05X in good condition?

YES : Go to Step 4.
NO :  Repair or replace the damaged component(s). Refer 

to GROUP 00E, Harness Connector Inspection 

P.00E-2

. Verify that the fog lamps illuminate normally.

STEP 4. Check the fog lamp relay.

Q: Is the fog lamp relay in good condition?

YES : Go to Step 5.
NO :  Replace the fog lamp relay. Verify that the fog lamps 

illuminate normally.

AC305979 AB

CONNECTOR: A-05X

RELAY BOX SIDE

FRONT OF VEHICLE

BATTERY VOLTAGE

TESTER 
CONNECTION

SPECIFIED 
CONDITION

Not applied

1 

− 4

Open circuit

• Connect terminal 2 

to the positive 
battery terminal

• Connect terminal 3 

to the negative 
battery terminal

1 

− 4

Less than 2 ohms

1

4

3

2

AC306645

2

1

3 4

FRONT OF 
VEHICLE

FOG LIGHT RELAY

AB

CONNECTOR: A-05X

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-343

STEP 5. Check the battery power supply circuit to the fog 
lamp relay. Measure the voltage at fog lamp relay 
connector A-05X.

CAUTION

The top and bottom of the fog lamp relay are difficult to 
identify. Prior to inspection, confirm the triangle mark on 
the relay box.
(1) Disconnect fog lamp relay connector A-05X and measure 

the voltage available at the relay box side of the connector.

(2) Measure the voltage between terminal 1 and ground, and 

also between terminal 2 and ground.

• The voltage should measure approximately 12 volts 

(battery positive voltage).

Q: Is the measured voltage approximately 12 volts (battery 

positive voltage)?
YES : Go to Step 7.
NO :  Go to Step 6.

STEP 6. Check the wiring harness between fog lamp relay 
connector A-05X (terminals 1 and 2) and the battery.
Q: Is the wiring harness between fog lamp relay connector 

A-05X (terminals 1 and 2) and the battery 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. Verify that 
the fog lamps illuminate normally.

AC305979 AB

CONNECTOR: A-05X

RELAY BOX SIDE

FRONT OF VEHICLE

AC209365

CONNECTOR A-05X
(RELAY BOX SIDE)

EK

AC305979 AB

CONNECTOR: A-05X

RELAY BOX SIDE

FRONT OF VEHICLE

SYMPTOM PROCEDURES

SIMPLIFIED WIRING SYSTEM (SWS)

54B-344

STEP 7. Check front-ECU connector A-11X for loose, 
corroded or damaged terminals, or terminals pushed back 
in the connector.
Q: Is front-ECU connector A-11X in good condition?

YES : Go to Step 8.
NO :  Repair or replace the damaged component(s). Refer 

to GROUP 00E, Harness Connector Inspection 

P.00E-2

. Verify that the fog lamps illuminate normally.

STEP 8. Check the wiring harness between fog lamp relay 
connector A-05X (terminal 3) and front-ECU connector 
A-11X (terminal 11).
Q: Is the wiring harness between fog lamp relay connector 

A-05X (terminal 3) and front-ECU connector A-11X 
(terminal 11) in good condition?
YES : Go to Step 9.
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 fog lamps illuminate normally.

STEP 9. Replace the ECU.
(1) Replace the front-ECU.
(2) The fog lamps should illuminate normally.

Q: Do the fog lamps illuminate normally?

YES : No action is necessary and testing is complete.
NO :  Replace the ETACS-ECU. Verify that the fog lamps 

illuminate normally.

AC305979 AB

CONNECTOR: A-05X

RELAY BOX SIDE

FRONT OF VEHICLE

AC305987AB

CONNECTORS: A-05X, A-11X

RELAY BOX SIDE

A-11X

A-05X

A-05X

A-11X

FRONT OF VEHICLE

RELAY BOX SIDE