Q: Changed alternator and battert, light still on and car dieing

This may suggest a bad grounding issue or potentially a failing voltage regulator. This is a unit that regulates the charging of the battery by the alternator. Often times this will result in the alternator allowing too much power to be delivered to the battery resulting in damaging wires and prematurely sometimes destroying the battery. In other cases it may result in the alternator not supplying enough power to the battery, resulting in undercharging the battery or not charging it at all. In either case, I would recommend having an expert from YourMechanic come to your location to diagnose and properly test your vehicle’s charging system.