Current Output Test
- Connect an ammeter in series between positive battery terminal and alternator battery "+" terminal. Connect positive voltmeter lead to positive battery post and negative lead to negative battery post. See Fig 1. To avoid a battery explosion, ensure carbon pile rheostat is OFF before connecting to battery.
- Connect carbon pile rheostat to battery, ensuring carbon pile rheostat is in the OFF position before connecting to battery. Start engine and let idle.
- Turn on all accessories. Load battery with carbon pile rheostat to obtain maximum amp output. Maintain voltage at 13 volts or more. If ammeter reads within 15 amps of rated amp output, alternator is okay. If ammeter does not read within 15 amps of rated amp output, replace alternator. See ALTERNATOR SPECIFICATIONS .
Courtesy of GENERAL MOTORS CORP.