I have a 15 year old Kenmore Series 70 Electric Dryer, and recently put in a load of wet clothes, left for a few hours, and came home to find the dryer still running (clothes were very dry!), but it probably ran about three hours longer than it should have. I opened the door, and it turned off, no problem. This only happened once, but since that time, I can only get the dryer to run by using the timed cycle, and only then by setting the timer to 10 minutes or less. I'm tempted to simply replace the timer, but didn't know if anyone else has an idea whether this could involve a problem that is more than "just" replacing the timer.