Automotive Electrical and Electronic Systems Classroom Manual Fifth Edition Update by John F. Kershaw

166 Chapter Eight
Figure 8-46. GM CS AC generator (alternator) regulator
circuit. (Delphi Automotive Systems)
Figure 8-45. When AC generator (alternator) output
voltage reaches a maximum safe level, no current is
allowed in the rotor winding. (Delphi Automotive Systems)
no test hole to ground the regulator for full-field
testing. The regulator cannot be tested with an
ohmmeter; a special tester is required.
Motorcraft
At one time, Motorcraft AC generators used both
remote-mounted and integral solid-state regulators.
Motorcraft regulator terminals are designated
as follows:
• A or A connects the battery to the field
relay contacts.
• S connects the AC generator output to the
field relay coil.
• F connects the field coil to the regulator
transistors.
• I connects the ignition switch to the field
relay and regulator contacts (only on vehicles
with a warning lamp).
Ford began using a remote-mounted, fully solidstate
regulator on its intermediate and large models
in 1978. The functions of the I, A, 8, and F
terminals are identical to those of the transistorized
regulator. On systems with an ammeter,
the regulator is color coded blue or gray, and the
T terminal is not used. On warning lamp systems,
the regulator is black, and all terminals can be
used. The two models are not interchangeable,
and cannot be substituted for the earlier solidstate
unit with a relay or for an electromagnetic
regulator. However, Ford does provide red or
clear service replacement solid-state regulators,
which can be used with both systems.
The Motorcraft integral alternator/regulator
(JAR) introduced in 1985 uses an IC regulator,
which is also mounted on the outside of the rear
housing. This regulator differs from others because
it contains a circuit indicating when the battery is
being overcharged. It turns on the charge indicator
lamp if terminal A voltage is too high or too low, or
if the terminal 8 voltage signal is abnormal.
DaimlerChrysler
The DaimlerChrysler solid-state regulator depends
on a remotely mounted field relay to open and
close the isolated field or the A-circuit AC generator
field. The relay closes the circuit only when the
ignition switch is turned on. The voltage regulator
(Figure 8-47) contains two transistors that are
turned on and off by a Zener diode. The Zener
diode reacts to system voltage to start and stop field