The Headlamps (High-Beam) Do Not Light - Mitsubishi Electric Lancer Evolution-VII Workshop Manual

Inspection Procedure F-3
The headlamps (low-beam) do not light.
If the (low-beam) headlamp on neither side lights up, either the headlamp switch
input circuit system or the front-ECU may be defective.
MUT-II diagnosis code
When the ignition switch is in the LOCK (OFF) position, is the
diagnosis code output?
Check the MUT-II input signals.
D Headlamp switch
Measure at the front - ECU connector A-10X.
D Disconnect the connector and test on the relay box side.
D Voltage between terminal 3 and the body earth.
OK : System voltage
Replace front-ECU.
NOTES:
1. If only one of the headlamps fails to light up, check the headlamp bulb and the harness between
the front-ECU and the headlamps, and between the headlamps and body earth.
2. When failure is detected on the harness from the front-ECU to the battery, check and repair the
front-ECU No. 4 terminal (A-10X) as well.
Inspection Procedure F-4

The headlamps (high-beam) do not light.

If the (high-beam) headlamp on neither side lights up, either the dimmer switch
input circuit system or the front-ECU may be defective.
Are the headlamps (low-beam) operating normally?
Check the MUT-II input signals.
D Dimmer switch
Measure at the front - ECU connector A-10X.
D Disconnect the connector and test on the relay box side.
D Voltage between terminal 4 and the body earth.
OK : System voltage
Replace front-ECU.
NOTE
1. If only one of the headlamps fails to light up, check the headlamp bulb and the harness between
the front-ECU and the headlamps, and between the headlamps and body earth.
2. When failure is detected on the harness from the front-ECU to the battery, check and repair the
front-ECU No. 3 terminal (A-10X) as well.
SWS -
NO
OK
OK
YES
OK
OK
Troubleshooting
Probable cause
D Column switch fault
D front-ECU fault
D Harness or connector fault
YES
Diagnosis Code Chart (Refer to P.54B-3).
NG
Check the headlamp switch input circuit system (Refer to
P.54B-31, Inspection Procedure J-7).
NG
Check the following connector: A-10X
OK
Check the trouble
symptoms.
NG
Check the harness between the front-ECU and the battery,
and repair if necessary.
Probable cause
D Column switch fault
D front-ECU fault
D Harness or connector fault
NO
Check the headlamps (low-beam) (Refer to P.54B-21,
Inspection Procedure F-3).
NG
Check the dimmer switch input circuit system (Refer to
P.54B-31, Inspection Procedure J-7).
NG
Check the following connector: A-10X
OK
Check the trouble
symptoms.
NG
Check the harness between the front-ECU and the battery,
and repair if necessary.
54B-21
NG
Repair
NG
Repair