We have the same problem with our 1997 ES300. The alarm will suddenly turn itself on while the car is parked in the garage. The dealer replaced a switch in the trunk at the cost of $68 but to no avail. The problem persists!
By trial and error we have discovered that it only happens if the trunk has been opened and closed while only the driver's door is unlocked. If we unlock all doors, open and close the trunk lid, nothing happens. That represents a problem anywhere else but in our garage. In public places, if we open and close the trunk lid, we restart the engine, turn it off and lock all doors. Weird isn't it?
Anyway I am going to get in touch with the car dealer and relate my findings. If they manage to fix the problem I'll let you know.
Charles M. De Mets
demets@ptd.net
