8-128 METERS AND GAUGES - Circuit Diagram
CIRCUIT DIAGRAM
METER CIRCUIT
Ignition switch
q [Refer to
To turn-signal switch
[Refer to P.8-491
I
To seat belt timer
[Refer to P.8-661 P.8-511 -
To seat belt warning
buzzer [Refer to P.8-661
1.25-GBA
, ^.
To alternator 48,5!W III -1 / 1 , 1 '----f--d+ii$$j IRefer to P.8.371 D I
.I_ -0 dimmkr, passinq
‘I+,:’ ! I I I II -I
I r I I I II YI
;witch and light control y K
clay [Refer to P.8-461
To dome liaht 5--hIIII I
----m-w-
[Refer to P&47] -w
Combination meter
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AUDIO SYSTEM - Specifications 8-193
NOISE SOURCES
Source of Electrical System Noise
Ignition system
(1) Spark plug
(2) High tension cable
(3) Distributor Power generation system
(1) Ripple at contact between alternator
armature and carbon brush
(2) Spark from voltage regulator contact
!
Other electrical device
(1) Armature of wiper, blower and other
motors.
(2) Starter and switch when starting engine
(3) Spark from changeover switch
(4) Horn
(5) Contact of turn signal
(6) Loose contact of wiring harness
(7) Static electricity generated by tire or
generator drive-belt
(8) Voltage stability unit for instrument
Noise Sourse of Vehicle Equipment
Kind of noise
Whistling sound Equipment
Alternator Symptom of noise generation
Noise increases when accelerator pedal is
depressed and it subsides soon after engine
is stopped.
Scratching sound
Water temperature gauge unit Noise is produced while engine is running
and it persists for a while after engine
shutdown.
Fuel gauge unit Noise is produced at sudden acceleration,
driving on rough road or when ignition key is
placed to ON.
Jarring
Wish-wash,
wish-wash
Buzz, click Oil pressure switch
Flasher relay
Horn
Wiper motor
Washer motor Noise is produced with engine operation
and no noise is made when engine is idling.
Noise is produced with operation of turn
signal light
Noise is made when horn button is pressed
or released.
Whinning Noise is generated with the wiper speed.
Noise is made when washer is operated.
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AIR-CONDITIONING -Service Adjustment Procedures 24-41
COMPRESSOR NOISE NWLM
When investigating an air conditioning related noise, you must first know the conditions when the noise occurs.
These conditions are: weather, vehicle speed, in gear or neutral, engine temperature or any other special
conditions.
Noises that develop during air- conditioning operation can often be misleading. For example: what sounds like a
failed front bearing or connecting rod, may be caused by loose bolts, nuts, mounting brackets, or a loose clutch
assembly. Verify accessory drive belt tension (power
steering, alternator or air pump). Improper accessory drive belt
tension can cause a misleading noise when the compressor is engaged and little or no noise when the compressor
is disengaged.
Drive belts are speed sensitive. That is, at different engine speeds, and depending upon belt tension, belts can
develop unusual noises that are often mistaken for mechanical problems within the compressor.
Adjustment Procedures
(1) Select a quiet area for testing. Duplicate conditions as much as possible. Switch compressor on and off several
times to clearly identify compressor noise.
To duplicate high ambient conditions (high head pressure), restrict air-flow through
condenser. Install
manifold gauge set to make sure discharge pressure does not exceed 2,070 kPa (300 psi).
(2) Tighten all compressor mounting bolts, clutch mounting bolt, and compressor drive belt. Check to assure clutch
coil is tight (no rotation or wobble).
(3) Check refrigerant hoses for rubbing or interference that can cause unusual noises.
(4) Check refrigerant charge (See “Charging the System”).
(5) Recheck compressor noise as in Step 1.
(6) If noise still exists, loosen compressor mounting bolts and retorque. Repeat Step 1.
(7) If noise continues, replace compressor and repeat Step 1.
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