Mitsubishi Lancer Evolution IV, Workshop Manual

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CHASSIS ELECTRICAL –
Radio and Tape Player
54-45
RADIO AND TAPE PLAYER
TROUBLESHOOTING
There is noise when the engine is running.
Kind of Noise (Parenthe-
sized is how noise
sounds.) Symptom Cause Remedy
AM, FM: Ignition noise
(Popping, snapping,
crackling, buzzing)
D
Popping sound becomes
faster with the increase
of engine speed.
D
The noise is lost with
ignition switch turned to
ACC.
D
Mainly due to the
spark plugs.
D
Due to noise circula-
tion from elsewhere
D
Noise from the engine
Check the noise capacitor
and earth cable and
replace if necessary. (See
Fig. 1 and Fig. 2.)
AM, FM: Defogger noise
(1) (Murmuring) Occurs when the defogger
switch is turned to ON and
OFF. Noise produced by spark-
ing when the defogger
switch is turned to ON/
OFF enters the glass
antenna. Check the noise capacitor
and replace if necessary.
(See Fig. 1.)
AM, FM: Defogger noise
(2) (Snapping noise) Occurs when the defogger
switch is turned to ON. Noise produced by current
flowing in the defogger
enters the glass antenna. Check the choke coil and
replace if necessary.
(See Fig. 3.)
AM, FM: Defogger noise
(3) (Scratching, gaggling) Occurs when the defogger
switch is turned to ON with
print heater wire broken. Noise produced by spark-
ing where print heater is
broken enters the glass
antenna. Repair the print heater.
AM, FM: Wiper motor
noise (Humming, wheez-
ing) Sound becomes faster with
the increase of wiper speed
and is lost when the wiper is
stopped. Caused by sparking in
wiper motor brush. Replace the wiper motor.
FM: Mirror motor noise
(Humming, wheezing) Occurs when electric mirror
operates. Caused by sparking in
mirror motor brush. Replace the electric
motor.
Other electrical compo-
nents – Noise is emitted by some
electrical components in
long use. Repair or replace electri-
cal components.
Static electricity (Crack-
ling, crinkling)
D
Noise is stopped when
the vehicle comes to a
complete stop.
D
Noise becomes louder
when the clutch is
released.
Occurs when parts or
wiring move for some
reason and contact metal
parts of the body. Put parts or wiring into
position.
Various noises are produced
by body parts. Due to electrical detach-
ment of the hood, exhaust
pipe and muffler, suspen-
sion, etc. from the body. Tighten mounting bolts
securely. In many cases,
remedy of one part does
not eliminate the problem
due to incomplete earthing
elsewhere.
Caution
(1) Never let the noise filter contact a high tension cable. The noise filter could break down.
(2) Check that there is no external noise. This check is necessary to prevent misidentification of noise
sources.
(3) Noise prevention should be performed by eliminating noise sources in the descending order of loudness.