Wife called to say that the van wouldn't start and wouldn't give the key back. Got home and everything was plumb dead, door locks wouldn't even lock. I threw jumper cables on it and it started instantly. None of the wait, none of the chugging, just instant start. Took the jumper cables off and it let it run for about five minutes. Turned it off and it gave the key back. Tried to turn it on again and instantly dead, won't give the key back. Doesn't sound like the starter, alternator or battery...any ideas?