Rotation of the excited field coil generates AC volt-
age in the stator.
This alternating current is rectified through diodes to
DC voltage having a waveform shown in the illustra-
tion at left.
The average output voltage fluctuates slightly with
the generator load condition.

When the ignition switch is turned on, current flows in
the field coil and initial excitation of the field coil
occurs.
When the stator coil begins to generate power after
the engine is started, the field coil is excited by the
output current of the stator coil.
The generator output voltage rises as the field cur-
rent increases and it falls as the field current
decreases. When the battery positive voltage (gener-
ator S terminal voltage) reaches a regulated voltage
of approximately 14.4 V, the field current is cut off.
When the battery positive voltage drops below the
regulated voltage, the voltage regulator regulates the
output voltage to a constant level by controlling the
field current.
In addition, when the field current is constant, the
generator output voltage rises as the engine speed
increases.

AKX00183

VOLTAGE

TIME

APPROXIMATELY
14.4 V

AK101130

GENERATOR

STATOR
COIL

FIELD COIL

CHARGING
WARNING LIGHT

IGNITION
SWITCH

BATTERY

VOLTAGE
REGULATOR

CHARGING SYSTEM

TSB Revision

ENGINE ELECTRICAL

16-3

CHARGING SYSTEM DIAGNOSIS

M1161000700104

TROUBLESHOOTING HINTS

Charging warning light dose not go on when the ignition switch

is turned to ON, before the engine starts.

• Check the bulb.

Charging warning light dose not switch off after the engine

starts.

• Check the IC voltage regulator inside the generator.

Discharged or overcharged battery.

• Check the IC voltage regulator inside the generator.

The charging warning light illuminates dimly.

• Check the diode (inside the combination meter) for a

short-circuit.

TROUBLESHOOTING GUIDE

The charging system troubleshooting guide is shown in the fol-
lowing steps.

STEP 1.
Q: Is the battery in good condition? (Refer to GROUP 54A,

Battery

− Battery check

P.54A-4

YES : Go to Step 2.
NO : Charge or replace the battery.

STEP 2.
Q: Is the generator drive belt in good condition? (Refer to

GROUP 00, Maintenance Service

P.00-39

YES : Go to Step 3.
NO : Adjust the belt tension or replace the belt.

STEP 3.
Q: Does the charging warning light shine brightly when the

ignition switch is turned on?
YES : Go to Step 4.
NO :

• Check the ignition switch. (Refer to GROUP 54,

Ignition switch

P.54A-31

• Check for burned- out charging warning light.

• Check the generator. (Refer to Generator −

Disassembly and assembly

P.16-15

• Check the charging warning light-related circuits.

STEP 4.
Q: Does the charging warning light go out after starting the

engine?
YES : Go to Step 5.
NO : Check the generator. (Refer to Generator

−

Disassembly and assembly

P.16-15

CHARGING SYSTEM

TSB Revision

ENGINE ELECTRICAL

16-4

STEP 5.
Q: Is an oscilloscope available?

YES : Go to Step 6.
NO : Go to Step 7.

STEP 6.
Q: Does the oscilloscope show a normal wave pattern?

(Refer to Charging system

− Wave pattern check using a

oscilloscope

P.16-9

YES : Go to Step 7.
NO : Check the generator. (Refer to Generator

−

Disassembly and assembly

P.16-15

STEP 7.

• Engine: 2,500 r/min

• Headlight: ON (high beam)

• Voltage between generator terminal B and the positive bat-

tery terminal
OK: 0.5 V or less

• Voltage between the negative battery terminal and genera-

tor body
OK: 0.5 V or less

Q: Are the generator output line and ground line in good

condition?
YES : Go to Step 8.
NO : Check the generator output line and ground line

STEP 8.
Q: Is the output current normal? (Refer to Charging system

− On vehicle service − Output current test

P.16-6

YES : Go to Step 9.
NO : Check the generator. (Refer to Generator

−

Disassembly and assembly

P.16-15

STEP 9.
Q: Is the regulated voltage normal? (Refer to Charging

system

− On vehicle service − Regulated voltage test

P.16-8

YES : Go to Step 10.
NO : Check the generator. (Refer to Generator

−

Disassembly and assembly

P.16-15

STEP 10.
Q: Is the voltage drop on the generator output line normal?

YES : Generator is normal. Check other systems.
NO : Check the output line.

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