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Current Output Test

CAUTION: DO NOT  run engine with alternator output terminal disconnected from battery.
  1. Connect an ammeter in series with alternator output cable. Connect positive voltmeter lead to positive battery post. Connect negative lead to negative battery post.
    CAUTION: Carbon pile testing is part of this procedure. To avoid battery explosion, turn carbon pile OFF before connecting to or disconnecting from vehicle battery.
  2. Ensure carbon pile control knob is in OFF position. Connect carbon pile to battery. If voltage is greater than 16 volts, repair or replace alternator. If voltage is less than 16 volts, go to next step.
  3. Start engine and run at moderate speed. Turn on all accessories except for heated windshield on vehicles so equipped. Load battery with carbon pile to obtain maximum alternator output. Adjust carbon pile to maintain voltage greater than 13 volts.
  4. If ammeter reading is within 15 amps of rated output, alternator is okay. If ammeter reading is not within 15 amps of rated output, repair or replace alternator.
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