I'm experiencing the same issue with the battery dying after a day or two left in the garage. I read others on this site with the exact symptoms. The car is being evaluated by a service tech this weekend. So far, he has had to jump it off twice just to test drive it. This is the 6th battery over the past several years so it is obviously something draining the battery. The dealership has charged several times to evaluate the problem and always comes back with instructions to drive it now, it should be good. Well, it's not good. It is a beautiful car, excellent shape and we would like to get to the bottom of this. Does Cadillac care? Crazy thought.

Anyway, the verdict is still pending so I will let you know what we find.

Advised dealer on 10/28/09 of problem. Took in on two other times Service representatives asked if we were leaving fobs in car (I said no, this would probably cause the car to get stolen,if thieves could get it started) They the said car was not being driven enough Currently have taken vehicle in for fourth time. Dealer has had it for four days and still not resolved.

I have a mechanic friend that says this problem is caused by an excessive parasitic draw. This mean that there is a system on the vehicle that is coming on when the ignition is switched off & runs till the battery is dead. This type problem is sometimes intermittent & hard to find. Scanning the body control module will sometimes lead to a fault code that will help repair the vehicle. I have seen everything from seat heaters, blower motor, rear window defogger, radio, or computer that will not go into the sleep mode & kill a battery.

I understand it is a hard problem to find but do not think driving it more will solve the problem