Output Test
- With ignition switch off, check voltage at "R" terminal and "L" terminal. Reading at both terminals should be 0 volts. If not 0 volts, alternator is defective.
- Turn ignition switch on but do not start engine. Voltage at "L" should be 1-3 volts. If voltage is 0, alternator and regulator are defective.
- If voltage at "L" is close to battery voltage with ignition on, short circuit the "F" terminal to rear alternator housing. See Fig 1.
- Read the voltage at "L" with "F" terminal shorted. If voltage is lower than battery voltage, regulator is defective. If voltage is close to battery voltage, alternator is defective.
- With ignition switch off and battery ground cable disconnected, connect ammeter between alternator terminal "B" and cable. Connect voltmeter between "B" (+) terminal and ground. See Fig. 2.
- Start engine and accelerate to 2000-3000 RPM. Turn on all lights and check ammeter for output.