Alternators, A Good Example of What's Wrong, GM, Ford, and Chrysler
In the beginning there was the third brush d.c. generator. It required an
external control (cutout relay & voltage regulator). Mechanics found it
easy to diagnose and service.
Then there was the two-brush d.c. generator. It required an external
control (cutout relay, voltage regulator and current limiter). Mechanics
found this also easy to diagnose and service.
The early a.c. generators (alternators) where configured similar to the
third brush d.c. generators. It had a simple external regulator. It was
easy to service.
Then came on line the solid state regulators used with alternators. This
was an improvement over the old vibrating relays. This was reliable and
easy to service.
The epitomy in charging system design was the self-contained
alternator-regulator. The Bosch was compact, easy to service and
exceedingly reliable. It consisted of an alternator and an attached
sold-state voltage regulator, that's all. A Bosch self-contained unit was
not only easy to diagnose and repair, it was most economical for the car
owner. By far, this was and remains the best automotive battery charging
Now we have the abysmal EFI integrated systems whereby your alternator with
its rectifier is bolted on the engine and its control (regulator) is part
of the EFI system. The usual arrangement is alternator to power module to
logic unit. This is the problem:
Diagnosis of the Bosch all-in-one charging system takes 5 minutes, tops.
The mechanic knows whether the plug-in regulator is at fault or the
alternator itself, or the connecting wiring. There isn't much connecting
wiring, being as there is just one wire from the alternator output to the
Conversly, diagnosis of an EFI integrated system requires three pages of
step-by-step procedure in the shop manual. You may have to remove the
battery or other components to access the mult-connection connectors in
both the power module and the logic unit. I cannot begin to describe the
diagnosis procedures, but let it be known it can take hours if the problem
is deep within. Hours equals hundreds of dollars. WHAT'S WORSE, IF IT
TURNS OUT TO BE THE POWER MODULE OR LOGIC UNIT IS FAULTY, these expensive
large scale components have to be replaced, rather than an inexpensive,
discrete voltage regulator. The difference in parts price between a $20
Bosch voltage regulator plugin and a logic module is hundreds of dollars in
parts and hundreds of dollars in labor. For what good reason, I ask?
So, here you have it, hours vs minutes. Dollars vs hundreds of dollars.
One system requiring a highly trained factory mechanic vs one a gas station
attendant could do..
An ideal charging system is an integrated alternator. It has only two
wires out: The main output and a warning light output. It is diagnosed as
simply as this: If there is no charging voltage on the dash gauge, the
warning light comes on. Then the mechanic checks for voltage at the output
terminal. If good, the trouble is in the wiring to the battery. If bad,
the mechanic "bypasses" the regulator with a jumper. If the voltage comes
up, its the regulator - replace it; otherwise, its the alternator - repair
Thus, we have a simple, cheap to service charging system. One claim for
integrated EFI is the regulator can adjust charging voltage more finely for
ambient temperature, etc. Well an integrated regulator does the same thing
with a thermistor which senses the cooling air inducted through the
alternator. Why make something immensely complicated that can be made
absurdly simple? Why place the generator control in the power module where
it can fail and take condemn that whole expensive unit to the trashbin?
Show your contempt for manufacturers that make it virtually uneconomical to
service out-of-warranty systems by demanding discrete systems (ignition,
fuel, charging, starting, cooling).
EFI systems have hundreds of wires and a multitude of connectors, all
potentially trouble prone from fatigue failure and effects of corrosion.
Its great when new; but it is maddening and hugely expensive to fix. Be