Doors are locking on their own

I thought I was going crazy, I knew I had not locked my doors but the next day they were locked, over and over again. I have no reason to lock my doors in my own garage! Then I discovered that exactly forty seconds after closing the door the doors all locked! And every forty seconds afterwards the locks click all by themselves over and over again. The only thing I can do is leave the door ajar and it will not do this. I took it to the mechanic and he sprayed some cleaner on the locks but it is still doing it. Could some one please tell me what to do? Thank you!