Why my Garage door only goes up?

Answer 1

Remove the cover, will you see an assembly switch,looks like plastic screws.

There is an up switch and a down switch screw,there are contacts on each screw,

when the up contact reaches the up limit contact it tells the opener to stop

and that when the button is pushed again to travel down. You should read your manual

and look at the diagram of the opener to make sure all the parts are there and nothing is broken or missing. If something is broken it should be in the bottom pan.

If everything is ok then it is your circuit board.

If you do not have the manual,you can usually get it online from the MFG.