Pull Battery Cable To Test Alternator

In the pre computer days you could pull it off without damaging anything.

Pull battery cable to test alternator.

Pcm tcm electronic power steering radio etc. Doing this would allow you to check whether the alternator is putting out enough current to run the vehicle. Testing alternator by removing battery cable was a valid test back in the day before computers. But it s no longer a safe test to perform on a modern vehicle.

Connect it to the battery and it should read a little above 12 volts when its off and 13. Start vehicle and voltage on voltmeter should increase to around 13 volts and stabilize there. Can you test an alternator by removing battery cable. To do a quick check on an alternator i was told that you could start the car and then remove the negative battery cable.

A good alternator may indeed keep the engine running without the negative cable but this was never a good test. Use a volt meter to test the voltage. Community answer test alternator by connecting voltmeter on dc 20 red on positive battery terminal and black on negative battery terminal. Technically yes but that test can also wind up destroying all the electronics in your car.

If you re tempted to test an alternator by disconnecting the negative battery cable don t do it. What are your thoughts. If the engine cuts off it is a sure sign that the alternator has died.