Output Current Test

Fig. 3 Meter Hook-Up, Output Current Test:

1. Before performing the output current test, check and repair if necessary the following:
a. Check to make sure battery is in good condition. The battery should be partially discharged, with a fully charged battery the test will not conduct properly due to an insufficient load.
b. Check condition and tension of the alternator belt.
2. Turn ignition off, then disconnect battery ground cable.
3. Disconnect output lead from alternator ``B'' terminal.
4. Connect ammeter and voltmeter as follows:
a. Connect a DC ammeter in series between the ``B'' terminal and the disconnected output wire. Be sure negative lead of ammeter is connected to disconnected output wire as shown in Fig. 3.
b. Connect a digital voltmeter between alternator ``B'' terminal and ground. Connect the positive lead wire of the voltmeter to the alternator ``B'' terminal and the negative lead wire to ground Fig. 3.
5. Connect tachometer, then reconnect battery ground cable.
6. Voltmeter should read battery voltage. If voltmeter reads 0 volts check for a open in the wire between the alternator ``B'' terminal and battery negative terminal, a blown fusible link, or a poor ground.
7. Start engine, turn headlamps on, place blower on high speed.
8. Set engine speed to 2500 RPM and read ammeter, the ammeter reading must be higher then the limit value. The limit value for a 60 amp alternator is 42 amps minimum, and 52 amps for a 75 amp alternator.