For the last couple of weeks at times my garage door will not go down with either the remote or the button in the garage. It will go down if you hold the button that is in the garage down while the door goes down. Is this a short,when you do hit the button either one, it will act like it is going down then stop and go back up the light also flashes. If there are any other questions please let me know. How big of a job does this sound like?