I have a problem with the opener, it goes up fine, but when going down it stops(even when door not connected) goes back up. I installed sensor but I only have one side, (it is used opener from mother in law) but light doesn't light up. On back of opener it has 3 pronges, push button on 1 & 2, don't know if sensor hooked up to right one. let me know. 308-631-9328