Midtronics intellect EXP-1000, Instruction Manual

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Table 3: Alternator Decisions and Recommendations
Decision Action
NO PROBLEMS The system is showing normal output from the alternator. No problem detected.
NO OUTPUT
The alternator is not providing charging current to the battery.
√ Check the belts to ensure the alternator is rotating with the engine running.
Replace broken or slipping belts and retest.
√ Check all connections to and from the alternator, especially the connection
to the battery. If the connection is loose or heavily corroded, clean or replace
the cable and retest.
√ If the belts and connections are in good working condition, replace the alterna-
tor. (Older vehicles use external voltage regulators, which may require only
replacement of the voltage regulator.)
LOW OUTPUT The alternator is not providing enough current to power the system’s electrical
loads and charge the battery.
√ Check the belts to ensure the alternator is rotating with the engine running.
Replace broken or slipping belts and retest.
√ Check the connections from the alternator to the battery. If the connection is
loose or heavily corroded, clean or replace the cable and retest.
HIGH OUTPUT The voltage output from the alternator to the battery exceeds the normal
limits of a functioning regulator.
√ Check to ensure there are no loose connections and that the ground connection
is normal. If there are no connection problems, replace the regulator. (Most
alternators have a built-in regulator requiring you to replace the alternator. In
older vehicles that use external voltage regulators, you may need to replace
only the voltage regulator.)
The regulator controls voltage output based on the battery voltage, under-
hood temperature, and vehicle loads used. In other words, it controls the
maximum voltage the system can produce based on the current needs and
amount of current that can be produced by the spinning of the rotor in the
alternator. The normal high limit of a typical automotive regulator is 14.5
volts +/–0.5. Refer to the manufacturer specifications for the correct limit,
which may vary by vehicle type.
A high charging rate will overcharge the battery and may decrease its life and
cause it to fail. If the battery test decision is REPLACE and the charging system
test shows a HIGH OUTPUT, check the battery’s electrolyte levels. A symptom
of overcharging is battery fluid spewing through the vent caps, which causes low
electrolyte levels and will harm the battery.
Chapter 6: System Test