Without Load

Before proceeding with the following test, ensure the battery is fully charged, the alternator belts are tight, and that all applicable fuses and fusible links are satisfactory. Also, inspect alternator for damaged wiring and listen for abnormal noises while running.

Charging circuit test connections:

1. Connect a voltmeter and ammeter to alternator as follows, Fig. 5:
a. Disconnect wire from terminal B of alternator and connect it to (-) lead of ammeter.
b. Connect (+) lead of ammeter and voltmeter to terminal B of alternator.
c. Ground (-) lead of voltmeter.
2. Test circuit as follows:
a. With engine running at 2000 RPM, amperage should be 10 amps or less, and voltage should be between 13.5-15.1v. If voltage is above 15.1v, replace IC regulator. If voltage is below 13.5v, go to step b.
b. Stop engine. With terminal F grounded, start engine and check voltage at terminal B. If voltage is above 15.1v, replace IC regulator. If voltage is below 13.5v, repair or replace alternator as necessary.