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Output Test

  1. Ensure connections at battery, alternator, and starter are clean and tight. Ensure alternator, engine and body are properly grounded. Ensure alternator drive belt is tight and in good condition.
  2. Connect ammeter following manufacturer's instructions. Connect voltmeter leads to battery terminals. Start engine and increase engine speed to 3000 RPM. Adjust carbon pile on tester to obtain maximum alternator output. DO NOT allow voltage to go below 12.6 volts.
  3. Alternator output should equal alternator rated output, minus 16-20 amps. If reading is 16-20 below alternator rating, replace regulator and retest. If alternator output is still low, replace alternator.
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