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Test 1

  1. If charge indicator light is on when engine is running, turn ignition off. Check alternator belt condition and tension. Check electrical connections at battery and alternator. Repair as required. If alternator belt and electrical connections are okay, go to next step.
  2. Using a voltmeter, connect voltmeter leads between alternator terminal "B" and ground. See Fig 1. Turn ignition on (engine off). If voltmeter reads battery voltage, go to next step. If voltmeter reads zero volts, repair open in White wire between alternator terminal "B" and Black 60-amp fusible link wire, located between battery and fusible link box. Fusible link box is located on left side of engine, behind battery.
    Fig 1: Identifying Alternator Terminals (Metro)
    G91F02011Courtesy of GENERAL MOTORS CORP.
  3. If voltmeter reads battery voltage in step 2), disconnect 2-wire alternator connector. Connect voltmeter between alternator connector Black/White wire (terminal IG) and ground. See Fig 1.
  4. Turn ignition on. If voltmeter reads about 12 volts, go to next step. If voltmeter reads zero volts, repair open in Black/White wire (terminal IG) between alternator connector and 20-amp ignition fuse at fuse box. Fuse box is located on bottom left side of dash. Also, check for an open between junction block Black/White wire and ignition switch.
  5. If voltmeter reads 12 volts in step 4), reconnect alternator 2-wire connector. Disconnect negative battery cable. Disconnect alternator terminal "B". Using an ammeter, connect Black ammeter lead to disconnected alternator terminal "B" wire and Red ammeter lead to alternator terminal "B".
    NOTE: During alternator output testing, use a slightly discharged battery. A fully charged battery may not allow full alternator output.
  6. Connect negative battery cable. Turn on all accessories, and set headlights on high beam and blower motor on high. Run engine as required to obtain maximum current output, and record ammeter reading.
  7. If alternator maximum current output is within 10 amps of alternator rated amp output, check battery connections and condition. See ALTERNATOR SPECIFICATIONS (METRO) . If maximum current output is not within 10 amps of alternator rated output, repair or replace alternator.
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