Alternator and Regulator Circuit Troubleshooting
  1. Be sure the battery is sufficiently charged.
  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 shift lever in Neutral, 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 voltage at the alternator terminal.
Is the voltage between 13.9 and 15.1 V?
YES -
Go to Step 6 .
NO -
Replace the alternator, or repair the alternator. ■
  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 87.5 A or more?
YES -
The charging system is OK. Go to alternator control circuit troubleshooting. ■
NO -
Replace the alternator, or repair the alternator. ■