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alternator testing
Posted: Wed Sep 30, 2009 1:23 pm
by nicklikesmilk
is it possible to test an alternator with just a handheld multimeter? my friend's car is having electrical trouble and i'd like to pinpoint the problem
Re: alternator testing
Posted: Wed Sep 30, 2009 6:08 pm
by Black Pearl
You could see if it's putting out 14 volts. The right way is to take the car and have a load test performed, that will tell you if it works under load.
Re: alternator testing
Posted: Wed Sep 30, 2009 9:00 pm
by markwb
A quick check is to connect a digital voltmeter across the (+) & (-) battery terminals to monitor battery voltage. Start the engine, allow voltage to stabilize after a few moments, it should be approximately 14.0 VDC. Have another person in the vehicle help out. Have them turn on some accessories like the Rear Window Defroster, Headlights, A/C etc. while you're monitoring battery voltage. The voltage will dip slightly at first with the loading on the electrical system then it should begin to increase again indicating that the alternator is delivering charge current.