Today you risk frying every electrical device in your vehicle.
Pull battery cable to test alternator.
What are your thoughts.
If you re tempted to test an alternator by disconnecting the negative battery cable don t do it.
Use a volt meter to test the voltage.
If the engine cuts off it is a sure sign that the alternator has died.
Can you test an alternator by removing battery cable.
But it s no longer a safe test to perform on a modern vehicle.
Pcm tcm electronic power steering radio etc.
Technically yes but that test can also wind up destroying all the electronics in your car.
Some newer cars will turn off even if the alternator is working good.
Community answer test alternator by connecting voltmeter on dc 20 red on positive battery terminal and black on negative battery terminal.
If it decreases and starts to drop until vehicle eventually dies you have a defective alternator.
Connect it to the battery and it should read a little above 12 volts when its off and 13.
A good alternator may indeed keep the engine running without the negative cable but this was never a good test.
In the pre computer days you could pull it off without damaging anything.
Testing alternator by removing battery cable was a valid test back in the day before computers.