Error codes on a Craftsman door opener?

Question

I'm actually asking this for my brother, because I am not certain of the answer.

He has a Craftsman 1/2 HP garage door opener that has recently started acting as though there was an obstruction in the way. He has cleaned and checked the sensors and it hasn't helped. If he holds the button down on the remote the door will close, but after it's shut there is a green LED on the motor/unit that flashes four times, pauses, flashes four times again and repeats for some time.

I'm wondering if anyone knows what the four flashes indicate and then, of course, if we can fix it. As it is right now the door will start down, stop, and go back up; unless he holds the button down.

And, of course, the house just went on the market.....

BTW, the unit is ten or eleven years old

Answer 1

check the lock button on the interior switch if its flashing the lock button is on the light should be solid  

Answer 2

I have a 1/2 HP Craftsman garage door opener about 11 years old. Every so often I lose the secret code in order to use the entry pad outdoors. You might have lose your code, try reprogramming a new code in.

Jerry L

http://www.agreenearthonline4u.com