Well, I have had the same problem with random door openings without me being there. I had thought, and still do, that there was someone else in the neighborhood that matched my frequency. I was away for the weekend and just got back to find my garage door opened. I thought that it was strange, but when I tried to close it, the lights came on but the motor wouldn't work! Maybe the fact that the door opens frequently on it's own, in my case, was a sign of the motor going bad.