(My son's car). Battery suddenly started going dead after just a few hours when car is parked. We figured it was the old battery so we bought a new one. New battery is doing the same thing. We can't find anything that is "on" when the car is parked. Any suggestions on what might be causing this? Obviously there's a power drain somewhere but we can't find anything causing this, or why it suddenly started doing this. Alternator is OK, and new battery is OK too (both tested at shop). Any advice appreciated! Thanks.....