I had this same problem last year for several months. The clock would also stop working. The battery checked out fine, alternator replaced, still kept doing it. After bringing it in to the shop numerous times and being told by AAA that I'd used up all my free emergency road service for the year, the mechanic said a switch inside the driver's door was slipping and causing the electrical system to fail. He fixed it and all was fine for about six months. Then it happened again. The air conditioning started running warmer, so I turned off the motor and when I tried to restart it, all I got was a click click sound. AAA came out and it started right away of course. Fifteen minutes after he left, the motor cut off and wouldn't restart. Called AAA again. It wouldn't turn over, so he gave it a jump and it did. Took it to my mechanic. He had no trouble with it and could find nothing wrong. He checked the switches in both doors; they're fine. I saw that owners of Chevy Impalas reported a similar problem, but not Lumina owners. Any one else have this problem? A solution? Thanks!