ALTERNATOR TESTING

[drthrift035]

What is the simplest way to check an alternator outside of a vehicle to verify before selling it ?

What if I just hook it up to a car battery and if it spins then it works ? Please let me know.

Topic

[college man]

The alternator should spin without hooking it up. You can take it
to an auto part store and have it tested which is not 100% or spin
the pulley and see if any noise is heard.

[Lorrin Barth]

If you want a 100% answer take it to a shop that repairs alternators and have them put it on their test apparatus.

[David]

Advance or Autozone can test the alternator, not sure what kind of load it puts on it, if any but it can tell you if you have an alternator problem or a problem with the PCM or wires.

[Gary]

Just hooking an alternator to a battery will not make it spin. An alternator spins by mechanical energy which is why it’s hooked up to a drivebelt. The alternator supplies current to the battery when the engine is running. You can spin the alternator by hand and look for bearing noise etc, but don’t expect it to spin on it’s own without some sort of driving force!

[EricTheCarGuy]

Easiest way when it’s out of the vehicle would be to take it to an auto parts store that can do that testing for you.

More info here.

http://www.ericthecarguy.com/faq/solving-automotive-electrical-problems

[Author]

Replies