I have a Craftsman 1/2 hp Garage Door Opener (41a5021) When I hit the button to close (wired or wireless) it does so, but when it hits the bottom, it immediately begins to open.
Any Ideas? Thanks
If you have the manual, It should explain how to adjust the up and down force adjustments on the opener. I believe the down force adjustment needs tweaked.
If the door hits the floor and then reverses it is closing a little too far. On the side of the motor unit you will find the 'down limit' control. Turn this a couple turns in the direction opposite the arrow printed on the cover. You may have to tweak this control a bit to get it just right.