How can I figure out why my Sears Craftsman garage door opener will not work?
If both sensor lights are not on, the door opener will not close and the light will blink because the opener thinks there is something in the door path. This is a safety measure. One light being off is usually due to either the two sensors getting out of alignment, a faulty connection, or a faulty sensor.  You say that you have installed new door sensors.  If both lights are still not on, you have to troubleshoot that first. Check all connections and then try to align the 2 sensors. If both green lights are on, and the opener will still not open, then the fault is probably elsewhere.