My 2003 Cadillac Escalade drained/ruined several batteries in about a 18 to 28 month period. No warning, just go to turn the key and the battery would be dead. Dealer never found the problem. The first time I had the car towed in with the dead battery still in it. They found nothing wrong except the bad battery. Currently the escalade has 60,000 miles and the problem has be dormant for about a year now. Unfortunately no one knows why. The only warning I remember is one time when starting the car it hesitated just like a battery will do when they are about to go bad. Most of the time it didn't give that warning. You just go out and find out your battery is dead. On one trip my wife and I went out to eat breakfast and the cad started perfectly normal when leaving the house. When we left the restaurant an hour later the battery was completely drained and bad. Fortunately for me NAPA and Advanced Auto stood behind the batteries as each time I took the battery in it checked it out bad and they replaced it. I think Cadillac has an electrical short somewhere they they don't know about or don't want to admit. Dave in Knoxville