System Output Test
- Check wiring harness electrical connections at generator. Check drive belt tension. See BELT TENSION under ADJUSTMENTS. Ensure battery is fully charged.
- Connect a voltmeter between ground and generator terminal "B". See Fig 1. Connect ammeter positive lead to generator terminal "B". Connect ammeter negative lead to to positive battery terminal on battery.
- To check generator no-load output, ensure all accessories are off. Start engine and allow it to idle. Increase engine speed to 2000 RPM and note output voltage and output amperage.
- If maximum current output is within 10 amps of rated amp output (55 amps) and voltmeter reading is 13.5-16.0 volts, generator is okay. If maximum current output is not within 10 amps of rated amp output and/or voltmeter reading is less than 13.5 volts, repair or replace generator.
Courtesy of GENERAL MOTORS CORP.