Mitsubishi Evolution X. Manual — part 945

HEADLIGHT

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CHASSIS ELECTRICAL

54A-141

Headlights Circuit <Discharge Type>

HEADLIGHT
ASSEMBLY
(RH)

HEADLIGHT
ASSEMBLY
(LH)

DISCHARGE-ECU

SOLENOID

SOLENOID

DISCHARGE-ECU

HEADLIGHT
RELAY (LOW)

HEADLIGHT
RELAY (HIGH)

RELAY
BOX

AC709111

Connectors: A-21X, A-29X

AE

A-21X

A-29X

AC708949AH

Connector: A-40

A-40 (B)

HEADLIGHT

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CHASSIS ELECTRICAL

54A-142

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TECHNICAL DESCRIPTION (COMMENT)

If any of the headlights does not Illuminate, the wiring
harness, connector(s), or the bulb may have a prob-
lem, or the fuse may be burned out.

.

TROUBLESHOOTING HINTS

• Malfunction of the headlight bulbs

• Malfunction of the headlight assembly

• Damaged harness wires and connectors

DIAGNOSIS

Required Special Tools:

• MB992006: Extra fine probe

• MB991223: Harness set

STEP 1. Check headlight assembly connector A-40 <LH>
or A-57 <RH>, for loose, corroded or damaged terminals,
or terminals pushed back in the connector.
Q: Is headlight assembly connector A-40 <LH> or A-57

<RH> in good condition?
YES : Go to Step 2.
NO : Repair or replace the damaged component(s). Refer

to GROUP 00E, Harness Connector Inspection

P.00E-2

.

STEP 2. Check bulb.
Check the bulb(s) of headlight that does not illuminate.
NOTE: If discharge-type lower beam headlights do not illumi-
nate, their bulbs cannot be inspected. In this case, assume the
bulbs to be normal and proceed with steps.
Q: Is the bulb in good condition?

YES : Go to Step 3.
NO : Replace the bulb(s) of the light that does not

illuminate.

AC708948AH

Connector: A-57

A-57 (B)

HEADLIGHT

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CHASSIS ELECTRICAL

54A-143

STEP 3. Check the wiring harness between headlight
assembly connector and headlight relay connector or
wiring harness between headlight assembly connector
and ground.
Check the power supply or ground line for open circuit.
<Halogen type headlight>

• Check the wiring harness between headlight assembly (LH)

connector A-40 (terminal 2) and headlight relay (LOW) con-
nector A-29X (terminal 3). <LH-LOW>

• Check the wiring harness between headlight assembly (LH)

connector A-40 (terminal 1) and headlight relay (HIGH) con-
nector A-21X (terminal 3). <LH-HIGH>

• Check the wiring harness between headlight assembly (LH)

connector A-40 (terminal 6) and ground. <LH-LOW and
HIGH>

• Check the wiring harness between headlight assembly (RH)

connector A-57 (terminal 2) and headlight relay (LOW) con-
nector A-29X (terminal 3). <RH-LOW>

• Check the wiring harness between headlight assembly (RH)

connector A-57 (terminal 1) and headlight relay (HIGH) con-
nector A-21X (terminal 3). <RH-HIGH>

• Check the wiring harness between headlight assembly (RH)

connector A-57 (terminal 6) and ground. <RH-LOW and
HIGH>

<Discharge type headlight>

• Check the wiring harness between headlight assembly (LH)

connector A-40 (terminal 12) and headlight relay (LOW)
connector A-29X (terminal 3). <LH-LOW>

• Check the wiring harness between headlight assembly (LH)

connector A-40 (terminal 1) and headlight relay (HIGH) con-
nector A-21X (terminal 3). <LH-HIGH>

• Check the wiring harness between headlight assembly (LH)

connector A-40 (terminal 5) and ground. <LH-LOW and
HIGH>

• Check the wiring harness between headlight assembly (RH)

connector A-57 (terminal 12) and headlight relay (LOW)
connector A-29X (terminal 3). <RH-LOW>

• Check the wiring harness between headlight assembly (RH)

connector A-57 (terminal 1) and headlight relay (HIGH) con-
nector A-21X (terminal 3). <RH-HIGH>

• Check the wiring harness between headlight assembly (RH)

connector A-57 (terminal 5) and ground. <RH-LOW and
HIGH>

Q: Is the wiring harness between headlight assembly

connector and headlight relay connector in good
condition?
YES : Replace the headlight assembly that does not

illuminate.

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 headlights illuminate normally.

HEADLIGHT

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CHASSIS ELECTRICAL

54A-144

Inspection Procedure 6: High-beam indicator light does not illuminate normally.

CAUTION

Whenever the ECU is replaced, ensure that the power supply circuit, the ground circuit and the com-
munication circuit are normal.

.

TECHNICAL DESCRIPTION (COMMENT)

If the high-beam indicator does not illuminate normally, the har-
ness in the CAN bus lines, connector(s), ETACS-ECU, or com-
bination meter may have a problem.

.

TROUBLESHOOTING HINTS

• Malfunction of the ETACS-ECU

• Malfunction of combination meter

• Damaged harness wires and connectors

DIAGNOSIS

Required Special Tools:

• MB991958: Scan Tool (M.U.T.-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: M.U.T.-III USB Cable

• MB991910: M.U.T.-III Main Harness A (Vehicles with

CAN communication system)

STEP 1. Check of headlight (high-beam).
Check that the headlights (high-beam) illuminate/extinguish
normally when the lighting switch is operated.
Q: Is the check result normal?

YES : Go to Step 2.
NO : Refer to Inspection Procedure 2 "All the headlights

(high-beam) do not illuminate

P.54A-133

."

INPUT SIGNAL

ETACS-ECU

DIMMER SWITCH

COMBINATION
METER

CAN COMMUNICATION LINE
(CAN_L LINE)

CAN COMMUNICATION LINE
(CAN_H LINE)

High-Beam Indicator Light Circuit