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Alternator and Regulator Circuit Troubleshooting

  1. Be sure the battery connections are good, and that the battery is sufficiently charged and in good condition.
  1. Hook up the following equipment:
    • Ammeter, 0−400 A
    • Voltmeter, 0−20 V (accurate within 0.1 V)
  1. Start the engine. Hold the engine at 3,000 rpm (min −1 ) with no load (in P or N (A/T model) or neutral (M/T model)), until the radiator fan comes on then let it idle.
  1. Raise the engine speed to 2,000 rpm (min −1 ) and hold it there.
  1. Turn the headlights (high beam) on, and measure the voltage at the alternator terminal.
Is the voltage within 13.9−15.1 V?
YES -
Go to Step 6 .
NO -
  1. Read the amperage at 13.5 V.
    NOTE: Adjust the voltage by turning the blower motor, rear window defogger, brake lights and etc. on.
Is the amperage 60 A or more?
YES -
NO -