In article . com,
"irish" wrote:

Do you have the light sensors at the bottom of the door to stop it if a
child or other object blocks the light. That will do exactly what you
decribe. it will go up but not down. Maybe the sensor has been blocked.

Second thing I checked. The closest thing to the sensor is more than 2
feet away. Is it possible that maybe one side or the other got knocked
out of kilter so the light isn't getting to the sensor?