TROUBLESHOOTING
31
3. Hold a vibration
-
type tachometer against the starter
frame.
4.
To operate the starter motor, connect a wire between
the positive battery
terminal and the S terminal on the
starter solenoid.
5. Note the starter
rpm, current draw and battery voltage
while the motor is running, then disconnect the wire to the
S terminal on the solenoid.
6.
If the starter motor does not perform within the specifi
-
cations listed in
Table
3,
repair or replace the motor as de
-
scribed in Chapter Nine.
CHARGING SYSTEM
The charging system consists of the alternator, voltage
regulator, battery, key switch, instrument panel warning
light, connecting wiring and fuse.
A belt driven by the engine crankshaft pulley turns the
alternator, which produces electrical energy to charge the
battery. As engine speed varies, the voltage output of the
alternator varies. The regulator maintains the voltage to
the electrical system within safe limits. The warning light
on the instrument panel signals if charging is not taking
place.
All models use a Hitachi alternator with an internal
transistorized voltage regulator attached to the rear alter
-
nator housing. Alternator output is 35 amps (model
LR135-05) or 55 amps (model LR155-20).
Figure
5
shows components of the charging circuit.
Charging system troubles are generally caused by a de
-
fective alternator, voltage regulator, battery or an inopera
-
tive charge lamp. They may also be caused by something
as simple as incorrect drive belt tension.
The following are symptoms of problems that may be
encountered.
1. Battery discharges frequently
-
This can be caused by
a drive belt that is slightly loose. Grasp the alternator pul
-
ley with both hands and
try
to turn it. If the pulley can be
turned without moving the belt, the drive belt is too loose.
As a rule, keep the belt tight enough so that it can be de
-
flected only about 112 in. under moderate thumb pressure
applied between the pulleys. The battery may also be at
fault; test the battery condition as described in Chapter
Nine.
2. Charging system warning lamp does not light when
key switch is turned ON
-
This may indicate a defective
key switch, battery, voltage regulator or warning lamp.
Try to start the engine. If it doesn't start, check the key
switch and battery. If the engine starts, remove and test the
warning lamp bulb. If the problem persists, the alternator
brushes may not be making contact. Perform the System
Circuitry Test in this chapter.
3. Charging system warning lamp jlashes on and
of-This usually indicates that the charging system is
working intermittently. Check drive belt tension first, then
check all electrical connections in the charging circuit. As
a last resort, check the alternator.
4.
Charging system warning lamp comes on and stays
on
-
This usually indicates that no charging is taking
place. First check drive belt tension, then the battery con
-
dition. Check all wiring connections in the charging sys
-
tem. If this does not locate the problem, check the
alternator and voltage regulator as described in this chap
-
ter.
5. Battery requires frequent addition of water or lamp re
-
quires frequent replacement
-
The alternator is probably
overcharging the battery. The voltage regulator is most
likely at fault.
6.
Excessive noise from the alternator
-
Check for loose
mounting brackets and bolts. The problem may also be
worn bearings or, in some cases, lack of lubrication. If an
alternator whines, a shorted diode may be the problem.
CHARGING SYSTEM TESTS
The alternator is equipped with an internal transistor
-
ized regulator. The transistorized regulator contains exci
-
tation and sensing circuits. The regulator controls output
voltage by switching the alternator rotor current on and
off. A rectifier consisting of a set of diodes converts alter
-
nating current to direct current.
Alternator Regulated Voltage Test
This test checks the regulated voltage output of the al
-
ternator. All wires connected to the alternator for normal
operation must be connected.
1. Check the alternator drive belt tension. See Chapter
Three.
2. Check the battery terminals and cables for corrosion
and/or loose connections. Disconnect the negative battery
cable, then the positive battery cable. Clean the cable
clamps and battery terminals, if necessary, then reconnect
the cables.
3. Check all wiring connections between the alternator
and engine to make sure they are clean and tight.
4.
Connect the positive lead of a voltmeter to the BAT ter
-
minal of the alternator. Connect the negative voltmeter
lead to the
E
terminal of the alternator. See
Figure
6.
5. Move the engine wire harness back and forth while ob
-
serving the voltmeter scale. The meter should indicate a
steady battery voltage reading (approximately 12 volts).
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