How To Check If Your Car Alternator Is Bad. It should be somewhere in the 12-to-13-volt range according to Hines. Lets see how to test the car alternator to make sure it is the part that has the problem.
In order to get a conclusive result as to whether an alternator has gone bad Hines says he uses a lot of fancy tools and expensive machinery. A good alternator may indeed keep the engine running without the negative cable but this was never a good test. A battery test is easy to perform and can be done at home.
Or if you are on your own with your car still running turn on your radio lights and any other electronic accessories and check the voltage reading.
Can you test an alternator out of the car. This varies by the model but when the. Another obvious sign is the one your vehicle tries to tell you. Take note of that number.
