On-Vehicle Test
- Disconnect battery cables and install cut-out switch, variable resistor, ammeter and voltmeter. See Fig 1. Connect ground cable and ensure that cut-out switch is in closed position.
- Start engine and run at 3000-4000 RPM (do not exceed manufacturer's RPM limits). Adjust variable resistor to give the following amperage readings: Models with 65 amp alternators, set to 45 amps; with 55 amp alternators, set to 25 amps.
- Open battery cut-out switch to isolate battery from test circuit. Load current is now determined by variable resistor. Readjust variable resistor to provide Test Output Amperage. Voltage should be between 13.1-14.4 volts. If not, replace regulator.
CAUTION:
Never run alternator without battery connected unless variable resistor is installed to provide load. Alternator, regulator or both could be severely damaged without providing current load.