I had the same problem around January 2001, it would go off in a campground when I got up at 4 AM to go fishing. I couldn't find anyplace low enough to hide in. The "dealer" took 4 or 5 try's, and finally had it happen on their lot a couple of times. Mine needed the temperature to be below 50*. I still get that feeling when I unlock it early in the morning while camping.
They replaced a Central Timer Module P/N 56045999AD. I don't know where it is located, the wife did all the dirty work, taking it to them and retrieving it.
Hope this helps.