if your car turns off while driving, than 2 things have to happend, your alternator stop supplying power tot he car, the car than reverts to using battery power(which is when the battery light would turn on), than it runs of the battery, when the battery is drained, the car will shut off...start your car and use a multi meter to check the alternator voltage output...could be a bad cable somewhere, these things to corrode with time...also check to make sure the cables to the alternator and tightened on...
