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Charging System Check

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When the charging system is operating normally, the charge indicator lamp will come on when the ignition switch is turned ON and will go out when the engine starts. If the lamp does not come on with the key ON you will need to check the warning light circuit or replace the bulb.

Keep in mind that an undercharged battery is often caused by accessories being left on overnight, or by a rear compartment or instrument panel compartment lamp that stays on.

Noise from an alternator may be caused by the following components:

  • Improper routing of hoses, wiring or shielding against the alternator housing.
  • A loose drive pulley
  • Loose mounting bolts
  • Worn or dirty bearings
  • A faulty diode
  • A faulty stator
  • Brush/slip ring friction

Precautions

  • Do not reverse the connections to the alternator.
  • Do not short across, or ground any of the terminals in the charging circuit, except as directed by the instructions.
  • Do not attempt to hot wire the alternator by connecting B+ voltage to any of the alternator 4-way connector terminals. Use only an approved test harness as described in these instructions.
  • Never disconnect the output terminal while the alternator is operating.
  • Use only approved terminal probe adapters to connect the meter leads and the jumper wires to the connector terminals. Using improper adapters will damage the terminals and cause charging system or test harness failure.

Inspection

Before testing the alternator inspect the following components and conditions:
  • Battery. Verily that the vehicle battery is in good condition and fully charged.
  • Built-in hydrometer in the battery. The green eye must be showing in the hydrometer.
  • The voltage across the battery terminals with all loads OFF should be above 12 volts.
  • Verify that the battery connections are clean and tight.
  • Drive belt for damage or looseness.
  • Wiring harness at the alternator. Verify that the harness connector is tight and latched. Verify that the output terminal of the alternator is connected to the vehicle battery positive alternator lead.
  • All charging system related fuses and electrical connections for damage or looseness.

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