Not sure if you have mentioned an external mount "keypad" or not, but I have just had a failure of an outside-mounted keypad. It has also lasted since 2004, but I guess moisture or usage finally killed it. The designers cleverly design these keypads so one must destroy them to look at the contact pads. I did this and did not see anything obvious. Replacement of the keypads are typically $20 which so far I have declined. I miss the convenience of the keypad. The other key pad is still working. I have had so called "phantom" openings but do not know what caused them. If you have car-mounted external clickers you probably know how easy it is to accidentally "click" and open a door. I make sure these clickers are placed where they cannot be banged around , including indoor storage in drawers. I take out the batteries if not in use.