Try the battery test. Turn the car ignition on and open the engine hood. While the car is running, remove the negative cable on the battery. If the car suddenly stalls and dies, your alternator could be bad. This is because the alternator is not generating enough electricity to keep the car running. If the car keeps running, the battery might be the problem.


NEVER, NEVER, NEVER disconnect the battery with the ignition switch on or the engine running. the unregulated voltage spike can ruin your sensitive electronic equipment including the PCM. use a voltmeter to check the voltage both engine off and engine running and with all electrical loads on. you may also check the current output by using a clamp on inductive ammeter to the alternator output wire.