9
STARTER DRAW TEST ChARGING SYSTEM OVERVIEW
When the engine is operating, the charging system converts mechanical energy into electrical energy to supply all of the car’s electrical systems
as well as to maintain the battery at full charge. The main components of the charging system are: an alternator (or generator), a regulator, a
battery, an in-dash indicator, and the wiring.
The
alternator
generates a certain level of amperage depending on the vehicle’s needs. The amperage output rating is usually stamped on the
alternator housing. If the alternator is faulty, the maximum amp output will be low. The F. ALTERNATOR OUTPUT TEST measures this output.
The test also indicates the presence of any open diodes in the system.
The alternator must be limited in order to not supply more voltage than needed which could cause excessive wear and damage to the electrical
system.This is accomplished by the
regulator
which can be either internal (inside the alternator) or external. All external and some internal
regulators can be bypassed in the
G. REGuLATOR BYpASS TEST (FuLL FIELD)
to determine if low voltage is caused by the alternator or
regulator. The
H. VOLTAGE REGuLATOR TEST
should also be done to insure that the regulator is maintaining the proper amount of voltage after
the car has warmed up.
Loose or corroded terminal, connections and damaged or undersized wires can produce resistance which can cause the voltage to drop between
charging system components. The
J. VOLTAGE DROp TEST
can pinpoint the source of these problems.
DIAGnOSInG THE pROBLEM
Be sure to check the battery, all cables and connections, and belt
condition and tension before proceeding (see tests
B and C
)
CHARGInG SYSTEM SYMpTOMS
n
Ammeter, voltmeter, or
warning light indications.
n
Battery has low state of charge.
n
Alternator noise.
H. VOLTAGE
REGuLATOR TEST
G. REGuLATOR
BYpASS TEST
F. ALTERnATOR OuTpuT TEST
READInG Ok
OuTpuT Ok OR LOW
LED On
READInG LOW
OuTpuT LOW
OuTpuT Ok OR
LED OFF
InTERnAL
REGuLATOR
J. VOLTAGE DROp TEST
On CHARGInG SYSTEM
EXTERnAL
REGuLATOR
LED OFF
Ignition
Regulator
Alternator
Battery
Voltmeter
Field Circuit
Battery Circuit
REpLACE ALTERnATOR
ADJuST OR REpLACE
REGuLATOR
REpAIR / REpLACE WIRInG AnD
COnnECTIOnS AS nECESSARY
REpLACE ALTERnATOR