Operation CHARM: Car repair manuals for everyone.

With 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. Run engine at 2000 RPM, turn on high beam headlights, and put blower switch on Hi position.
3. Check amperage reading. If amperage is 30 amps or above, alternator is good. If amperage is below 30 amps, repair or replace alternator as necessary.