I inherited a '92 240 in Jan. 06. It has low mileage 58,000. It sat outside unused for about 18 months prior to that.(I know this is bad for a car) It worked fine until June when the ignition ding- ding sound came on and wouldn't stop. The battery died subsequently and our mechanic checked for shorts and couldn't find any and disconnected the ding-ding(ignition I think). We replaced the battery because it didn't seem to hold a charge after this incident and all was fine for 2 weeks when it died again. The mechanic, still stumped and pretty sure the problem is something simple, disconnected the trunk light and the radio antenea. It started up fine for a few days, but after sitting for 48 hours is dead again. Any idea would be appreciated. Thanks