7
SECTION 55 – ELECTRICAL SYSTEM – CHAPTER 4
603.54.331.00 – 12 – 1996
If the voltmeter reading is higher than 14 V or 14.4
V, for Magneti Marelli or Bosch alternators respec-
tively, the alternator regulator must be changed, as
described in this section. (After installing a new
regulator, carry out tests 4 and 5).
If the voltmeter reading is less than 13.6 V, there is
either a faulty component in the alternator or a
failure due to excessive resistance in the external
charging system connections.
If the ammeter reads zero amps, then one of the
alternator components is malfunctioning. Turn the
engine off and carry out the alternator component
test, as described in this chapter.
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3. CHARGING CIRCUIT VOLTAGE DROP TESTS
(a) Insulated side voltage drop test
See figure 7.
Check the ignition key is in OFF position.
1. Disconnect the negative battery cable and the
B+ alternator wire (1).
2. Connect a millivoltmeter (5) between the
positive battery terminal clamp and D+ wire (3)
(positive side of the wire)
3. Connect an ammeter (2) between the B+
alternator terminal and the D+ wire (negative
side of the wire).
4. Reconnect the negative battery cable and
connect a varying load resistance (4) with
cursor in minimum current absorption position
(maximum resistance) through the battery
terminal clamps.
5. Start the engine and increase speed to 2000
rev/min.
6. Decrease resistance charging load (decreas-
ing resistance) slowly until the ammeter reads
45 or 65 A. according to the type of alternator.
7. Note the reading on the millivoltmeter. This
must not be higher than 400 millivolts.
A reading higher than 400 millivolts indicates mal-
functioning due to excessive resistance in the
external circuits.
If the alternator does not output required power and
the millivoltmeter reading is less than 400 millivolts,
there is a malfunctioning component in the alterna-
tor. Carry out the alternator component tests, as
described in this section.
8. Stop the engine.
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