I'm also having temperature related problems with my Craftsman 139.53985 1/2 HP opener.

When the temperature is between 15 to 30F the opener sometimes "goes dead". Below and above this range it works fine. The problem is usually the door will not open at all when using the wall control when the green led is off. The remote doesn't work either.

I unplugged the unit for 30 seconds and after plugging it back in the green led came on dimly but was flickering. I again unplugged the unit again waiting about a minute this time before plugging it back in. This second attempt causes the LED to be on solid. First attempt at opening the door results in the door opening halfway. Depressing the wall control again closes the door. The third attempt usually succeeds and the opener will work for a few days. I've checked all connections for continuity. Any suggestions would be appreciated.