I have 1/2 hp craftman chain GDO. It works just fine when it is above 35 degrees, but will not shut when the temperature drops below 35. It will shut about half way and then open back up, and I have to shut it manually. After I close the door and hit the button the chain runs and it will click into the release lever. my first thought was there was water in the sensors, but that is not the case. Any ideas?