I have a flakey 1995 vintage Sears Craftsman garage door opener (#41A4315-6C). It seems like the connector that attaches to both the transmitter and receiver is not making good contact. By inserting to connector about 1/2 way and wiggling the wire a little, I can get the green led's to come on and make to door work. It never seems to work if I simply push the connector all the way on.
It seems possible that either the connector or the pins on the sensors are dirty. I have cleaned them, however, as best I could. Did the wire for the units come with the connector already on it? I would take the connector off and reconnect it if I could figure out how.
Then I wonder if the circuit board inside the sensors could be defective. Perhaps when I wiggle the wire I'm flexing the printed circuit board and enabling contact. You can't take the sensors apart, however. I wonder how I could check them out. Has anyone has had experience with flakey sensors?