2005 MITSUBISHI 380 low beam

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-253
STEP 3. Check the input signal by using "FUNCTION
DIAG." menu of the SWS monitor.
Check the input signals from the following switches:
Ignition switch: ACC
Windshield washer switch: ON
(1) Operate the Diagnostic Tool MB991958 according to the
procedure below to display "F.WIPER WASH."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "WIPER."
g. Select "F.WIPER WASH."
(2) Check that normal conditions are displayed for the items
described in the table below.
Q: Are normal conditions displayed for "FRONT
WASH.SW" and "FRONT ECU ACK"?
Normal conditions displayed for all the items : Go to
St e p 4 .
Normal condition is not displayed for the "FRONT
WASH.SW" : Replace the column switch. Verify that the
windshield washer works normally.
Normal condition is not displayed for the "FRONT ECU
ACK" : Replace the front-ECU. Verify that the windshield
washer works normally.
STEP 4. Check windshield washer motor connector A-29
for loose, corroded or damaged terminals, or terminals
pushed back in the connector.
Q: Is windshield washer motor connector A-29 in good
condition?
YES : Go to Step 5.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Verify that the windshield washer works
normally. ITEM NO. ITEM NAME NORMAL
CONDITION
ITEM 09 FRONT WASH.SW ON
ITEM 70 FRONT ECU ACK NORMAL ACK or
HI-BEAM ACK

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-257
HEADLAMP AND TAILLAMP
GENERAL DESCRIPTION CONCERNING THE HEADLAMPS AND TAILLAMPSM1549021300264
Refer to circuit diagrams GROUP-90
Refer to configuration diagrams GROUP-80The following ECUs affect the functions and control
of the headlamps and the taillamps.
FUNCTION CONTROL ECU
Taillamps Front-ECU, column switch
Headlamps ETACS-ECU, front-ECU, column switch
High-beam indicator lamp ETACS-ECU, column switch
Headlamp automatic-shutoff function ETACS-ECU, front-ECU, column switch
Dimmer automatic reset function Front-ECU, column switch

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-258
Taillamps and headlamps illumination
.
Taillamps
If the column switch sends a taillamp switch "ON" signal to the
front-ECU, the front-ECU turns on its taillamp relay, causing the
taillamps to illuminate.
NOTE: This description covers the taillamps only. In actual driv-
ing, the taillamps may be turned off due to the headlamp auto-
matic shut-off function. For the details of the headlamp
automatic shut-off function, refer to .
.
Headlamps
If the column switch sends a headlamp switch "ON"
signal to the front-ECU, the front-ECU turns on its
headlamp relay (LOW), causing the low-beam
headlamps to illuminate. If the dimmer switch is
turned on while the headlamp relay (LOW) is on, the
front-ECU turns on the headlamp relay (HIGH),
causing the high-beam headlamps to illuminate.NOTE: This description covers the headlamps only.
In actual driving, the headlamps may be turned off
due to the headlamp automatic shut-off function. For
the details of the headlamp automatic shut-off func-
tion, refer to .
High-beam indicator lamp
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.

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-259
Headlamp automatic-shutdown function
Even if the lighting switch (taillamps switch or headlamp switch)
is ON, the headlamps (including the taillamps) will automati-
cally go off in the following conditions to prevent the battery
from discharging as a result of forgetting to turn off lamps.
If 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 headlamps will automati-
cally be turned off. If the driver's seat door is opened during
these three minutes, the headlamps will go off one second
later.
NOTE: The headlamp automatic-shutoff function can be cus-
tomized on vehicles equipped with a multi center display (mid-
dle grade type). Refer to P.54B-486.
Dimmer automatic reset function
If the headlamp switch is turned off while the high-beam
headlamps are on, the dimmer switch will be reset. Because of
this, the headlamps will illuminate at low beam the next time
that they are turned on. The dimmer switch will be also reset if
the dimmer switch is turned on unintentionally while the pass-
ing switch is operated.

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-264
STEP 5. Check the wiring harness between front-ECU
connector A-11X (terminal 7) and the battery.
Q: Is the wiring harness between front-ECU connector
A-11X (terminal 7) 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 taillamps illuminate normally.
INSPECTION PROCEDURE H-2: Headlamp and Taillamp: The headlamps (low-beam) do not illuminate
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
When the lighting switch is set to "HEAD" posi-
tion, the "HEAD" signal is sent through the col-
umn-ECU (incorporated in the column switch) to
the front-ECU. If the front-ECU receives the
"HEAD" signal through the column-ECU, the
front-ECU turns on the headlamp relay (incorpo-
rated in the front-ECU), thus causing the
headlamps to illuminate. The headlamps always
illuminate at low-beam by the headlamp dimmer
switch automatic resetting function.
If the SWS communication line is defective, the
front-ECU operates the headlamps by using the
other communication lines (headlamp backup cir-
cuit) instead of that line.
.
TECHNICAL DESCRIPTION (COMMENT)
If the headlamps (low-beam) do not illuminate nor-
mally, the column switch or the front-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 front-ECU may be defective
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

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-266
STEP 2. Check the input signal by using "FUNCTION
DIAG." menu of the SWS monitor.
Check the input signals from the following switches:
Ignition switch: ON
Lighting switch: HEAD
(1) Operate Diagnostic Tool MB991958 according to the
procedure below to display "HEADLAMP LO."
a. Select "Interactive Diagnosis."
b. Select "System select."
c. Select "SWS."
d. Select "SWS MONITOR."
e. Select "Function Diag."
f. Select "LIGHTING."
g. Select "HEADLAMP LO."
(2) Check that normal conditions are displayed for the items
described in the table below.
Q: Does the Diagnostic Tool MB991958 display the items
"HEADLAMP SW", "H/L AUTO-CUT" and "FRONT ECU
ACK" as normal condition?
Normal conditions are displayed for all the items : Go to
St e p 3 .
Normal condition is not displayed for "HEADLAMP SW"
: Refer to Inspection Procedure M-5 "ETACS-ECU
does not receive any signal from the headlamp switch
P.54B-420."
Normal condition is not displayed for "H/L AUTO-CUT" :
Refer to Inspection Procedure H-9 "Headlamp
automatic shutoff function does not work normally
P.54B-305."
Normal condition is not displayed for "FRONT ECU
ACK" : Replace the front-ECU. Verify that the headlamps
(low-beam) illuminate normally. ITEM NO. ITEM NAME NORMAL
CONDITION
ITEM 00 HEADLAMP SW ON
ITEM 35 H/L AUTO-CUT OFF
ITEM 70 FRONT ECU ACK NORMAL ACK

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-267
STEP 3. 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 4.
NO : Repair or replace the damaged component(s). Refer
to GROUP 00E, Harness Connector Inspection
P.00E-2. Verify that the headlamps (low-beam)
illuminate normally.
STEP 4. Check the battery power supply circuit to the
front-ECU. Measure the voltage at front-ECU connector
A-11X.
(1) Disconnect front-ECU connector A-11X and measure the
voltage available at the relay box side of the connector.
(2) Measure the voltage between terminal numbers 8 and
ground, and also between terminal 9 and ground.
The voltage should measure approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approximately 12 volts (battery
positive voltage)?
YES : Replace the front-ECU. Verify that the headlamps
(low-beam) illuminate normally.
NO : Go to Step 5.

SYMPTOM PROCEDURES
SIMPLIFIED WIRING SYSTEM (SWS)54B-268
STEP 5. Check the wiring harness between front-ECU
connector A-11X (terminals 8 and 9) and the battery.
Q: Is the wiring harness between front-ECU connector
A-11X (terminals 8 and 9) 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 headlamps (low-beam) illuminate normally.
INSPECTION PROCEDURE H-3: Headlamp and Taillamp: The headlamps (high-beam) do not
Illuminate 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
When the dimmer switch is turned on, the column
switch sends a signal to the front-ECU. Then the
front-ECU switches the headlamps from low-beam to
high beam or vice versa.
.
TECHNICAL DESCRIPTION (COMMENT)
If the headlamps (high beam) do not illuminate nor-
mally, the column switch or the front-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 front-ECU may be defective
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