Question about Sears Craftsman LiftMaster Chamberlain Garage Door Opener Wireless Keypad Model 976LM Security+

1 Answer

Opening & closing by itself

We installed our 1/2 HP Craftsman Model 139.53985 back in April 2004.

In the past several months there have been a few occassions that the door has gone up and down on its own, but only up/down one or two times.

Overnight, we woke to hearing the door opening and closing over and over. I went out in the garage and looked at everything (didn't touch anything) and didn't see anything out of place. I stepped out when the door was up and looked at the outside remote keypad, then stepped back in the door.

At that time, it stopped going by itself and when I pushed the main control panel to close it, it stayed closed.

Seems this issue is getting worse, the manual troubleshooting page doesn't give much info for this but to remove the bell wire from the door controls and see if remote units work.

Does anyone know of any other situations that can cause this and how I may be able to fix it?

Thanks for your assistance!

Scott B

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  • Wayne Mineard
    Wayne Mineard May 11, 2010

    Did you make sure the sensors are aligned properly? Sounds like they may be off just enough to be toggling between blocked and unblocked.



    You may also need to check and adjust the down lmit also. If it is set to come down too far it will go back up.



    Just a couple thoughts offhand.

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  • 244 Answers

Above would not explain unit running in middle of night after door had been closed. I to would suggest taking off wire from motor (white and red). if problem stops, you have a short in wire or a bad pushbutton.

Posted on Jan 28, 2009

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