You have to have both lights lit on your sensors for your door to close. Right now it thinks there is something in the way and will only close if you hold the button down. The circuit board may be burned up if you have recently had a bad lightning storm. But first troubleshoot it this way. Take your new sensors back off and get on a ladder at the head unit. Wire your sensors directly to the craftsman head with short pieces of wire and point them directly at each other. If both lights come on, you have a break or short in the wires running to your safety eye mounts or you've wired the eyes backwards and your board is ok. Simply run new wires to the mounts( any kind of wire will do its low voltage and can't even shock you).If you have wired your eyes to the head and don't get any lights(keep in mind that one eye will always stay lit(the sender) and one will only light up when they are pointed at each other(the reciever) then try swapping your wires around at the head(they do have to be in specific places). If none of this works, your circuit board is probably blown, you can either call a professional(most service techs can bring a new board if you tell them your type of operator), replace the opener, or try to get a new board from the manufacturer. They're easy to swap, just make sure you unplug the unit first(they can shock)!! Been there.