The engine cut off at a stoplight, but it started right up, later all the light went dim and then you heard a snap everything was ok again. We put a new alternator in the car. Now it cuts off more, when its at a stop its cuts off, sometimes when you drive it acts like it going to cut off and snap its ok. Its happen when the lights are on and when they are off. But when you put the lights on the dash dims really low. Please help!