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

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Sears Craftsman 1/2Hp Garage Door Opener - Opens on its own

Brand new 315Mhz garage door opener opens and closes on its own. Noticed that this happens primarily in colder weather (< 10 degrees F). Caught the door opening and closing at 5AM which was very unsettling. Couple other times we caught it running on its own as well, not just once, but repeating its opening and closing cycle.
Deduced it was not related to any neighbors remote, or even any of ours. Figure it must be the circuit board and have to call Sears to either get the CB replaced or the whole unit. Kind of a security issue.

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  • Debbie
    Debbie Dec 30, 2008

    I'm pretty sure ours is a Sears as well. It'll open on its own, which is unnerving enough but when we use an opener (either wall or remote) it will only open about 8 inches (frustrating!). I discovered I can get it up all the way by helping it along. It only started about 3 weeks ago when it started getting really cold. I put the vacation lock on but that's still seems to be possessed and opens at random times overnight or early in the morning.

  • danny2312 Jan 03, 2009

    I have the same problem. My door will open and close on its own. I have to pull the release cord every night and lock it manually for security reasons. No one at Sears can help me.

  • Anonymous Jan 25, 2009

    I installed a Chamberlain 1/2 HP screw drive opener in Oct 2008. We've had 4 instances (so far) since then where the door opens on its own, overnight. These all happened in December & January, so perhaps the cold does play a part.

  • wlois1 Jan 26, 2009

    I had Sears maintenance come out and look into the problem. They replaced the circuit board in the opener itself, however, it did not solve the problem as the door has now opened itself twice since they "fixed" the problem. Both times in cold weather. I now suspect this problem to be related to the wall unit circuit board having a short. Since at times when it acts up, the green light on the wall control is not lit as it should be.

  • tractorgy Mar 12, 2009

    We installed a new door opener model 139.53985DM, 315mhz, a few days ago. During a cold snap thr door opened and closed several times

    by itself. Sears repair people are due here in couple of days. I'll tell

    them the new circut board may not work. If they something different,

    I'll post that



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There are three causes for this problem:
1. a remote is sticking or is getting bumped (if the vacation lock is on and it still has phantom operation remotes are not the issue).
2. the logic board could be going bad (if you have the 315Mhz you have a newer operator so this is probably not your issue)
3. the wires to the wall button have a short. Try disconnecting the wall button wires from the operator. If this stopps the phantom operaton you might solve your issue by running new wires to your wall button.

Posted on Jan 03, 2009

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I also had this problem numerous times during cold weather and have solved the issue. The problem is the result of a poor mechanical design with the in garage open/close button on the remote control unit. The remote control unit utilizes two momentary contact switches mounted to the printed circuit board with a black plastic piece that is supposed to slide in relative to the control unit when pressed. The black plastic piece is then supposed to slide back out after it is released. This motion is supposed to be driven by two cantilever springs that are part of the main housing. Because the red plastic housing is not stiff enough and because the printed circuit board's location is not precisely controlled relative to the housing, the black plastic piece can become slightly wedged and not fully slide back out. Due to thermal expansion/contraction issues, the wedged black piece can then make contact with the switches as the temperature changes. To fix the problem, I removed the black plastic piece, cut off the two plastic bars that are supposed to make contact with the contact switches and wired an external switch to the unit that I now use to open and close the garage door. I then cut off the two black bars that were used to contact the switches on the printed circuit board and reinstalled the disabled black piece. Since I have made this modification, the problem has been resolved!

Posted on Sep 05, 2012


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