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SECTION 55 -- ELECTRICAL SYSTEM -- CHAPTER 4
603.54.471.00 -- 11 -- 2004
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1. ALTERNATOR WIRE CONNECTIONS TEST
Seefigure5.
1. Disconnect the battery.
2. Disconnect B+ (2) and D+ (3) alternator
terminals.
3. Reconnect the battery and turn the ignition key
into position ON but without starting the engine.
Connect a voltmeter (4) between each terminal
and earth (ground) (1). There must be voltage
at the battery.
If there is no voltage at the battery, check for a
continuity fault in the external wiring. See circuit
diagram in figure 2.
4. Connect D+ terminal, warning light wire (red)
and earth (ground). The warning light should
illuminate.
5. Disconnect the battery and reconnect the
cables to the alternator at (2) and (3) fig. 5.
NOTE: If the warning light does not light up when
the wire is connected to the alternator, this means
that there is a fault either in the alternator regulator
circuit or in the rotor circuit. Check D+ terminal is
clean and then test the alternator components as
described in this section.
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2. CHARGING CURRENT AND REGULATED VOLT-
AGE TESTS
Seefigure6.
1. Check that all tractor electrical devices are
switched off and the ignition key is in the OFF
position.
2. Disconnect the negative battery terminal clamp
and the B+ negative alternator terminal.
3. Connect an ammeter (1) between the
disconnected wire (red) (4) and the B+
alternator terminal (3).
4. Connect a voltmeter (2) between the B+
alternator terminal (3) and earth (ground).
5. Reconnect the battery. Start the engine and run
it at 2000 rev/min. Note the readings on the
voltmeter and the ammeter.
The voltmeter reading should be higher than the
battery voltage and when the ammeter reading falls
below 10 A, the voltmeter reading should stabilise
at 13.6 -- 14 V (Magneti Marelli alternator) or 13.6 --
14.4 V (Bosch alternator).
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26644
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