Alternator (Generator; Alternator. Basic; Alternator With Multi-Function Control (Mfr - BMW 5251 Service Manual

121-11
Battery, Starter, ~lternatorl
Alternator
1997
-
98 5281
1997 540i
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F15
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30
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Battery
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in run
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(D+)
Alternator
and stsrt
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Alternator, basic
On 1997-1 998 6-cylinderand 1997 V-8 models, the charging
system indicator light is supplied voltage (+) to one side of the
light bulb, and the other side of the bulb is connected to the
voltage regulator.
With the engine off and the key in the run position, voltage
from the ignition switch flows through the regulator to ground,
completing the circuit and illuminating the charge indicator
bulb.
When the vehicle is started and the alternator begins to pro-
duce voltage, the output of the diode trio increases and the
light is turned off.
Alternator with
multi-function control (MFR)
Alternator with multi-function control
(MFR)
The multi-function controlled alternator is used on:
*
1999-2002 6-cylinder models
*
1998-2002 V-8 models
4
On cars with multi-function control alternator, the charge in-
dicator lamp is activated by means of an electronic switch in-
tegrated in the alternator controller. This switch receives its
voltage supply from terminal 15 on the 3-pin connector at the
rear of the alternator. The controller measures internally the
voltage difference between terminal 30 and terminal 15 and
signals the DME ECM to turn the charge indicator lamp on.
The controller features integrated fault detection. The battery
charge indicator lamp will come on in the event of:
*
Failure of belt drive
No charge due to an electrical/electronic fault
Interruption in excitation circuit
Over-voltage due to a defective controller output stage
Fault or break in charge line
No charge due to alternator fault