This morning my garage door opener stopped working correctly. It was working fine, as of last night. I have a Liftmaster Professional 1250LM (1/3 HP).

Prior to this morning, the sensor had not been touched. I've made sure that they are level and correctly pointed at each other. Each has a solid (non-blinking) green light. Lock mode doesn't appear to be on.

When I press the button on either of our 2 clickers, the light just flashes and the door does nothing. As if something is blocking the sensors.

If I quickly press the button on the wall panel, the same thing happens. However, if I hold it down, the door will close. Not sure but, this seems to force it to go, despite the sensor reading. Tapping it again, once the door has closed, opens the door normally. When closing the door, I have to hold down the button on the wall panel until it's completely closed or it will stop. Again, as if something is blocking the sensor.

In either of these cases (the door has been "forced" open or close), the remote does nothing but make the light flash.

Any thoughts on what the issue might be?

  • 1
    If you block a sensor do the lights change?
    – isherwood
    Nov 30, 2016 at 16:06
  • Liftmaster has an amazing support desk. They also talk to anyone, regardless of warranty. Give them a call.
    – Tyson
    Nov 30, 2016 at 16:17
  • @isherwood - I just checked and no, they do not seem to change, when blocked.
    – Batfan
    Nov 30, 2016 at 16:20

1 Answer 1



After spending a few days trying to decipher the troubleshooting instructions Liftmaster sent me, I've resolved this issue.


As I mentioned originally, I could hold the button down on the wall control to "force" the door down. I did this and then waved something in front of the sensors. This reversed the door. So, the sensors are working fine.

I ended up pressing the green "Smart" button on the back of the main unit and then pressing the remote button once. This seems to have re-added the remote to the system. Both remotes work normally now.

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