Where do the grey wires in the nut go? Are they the third wire in the cable going to the sensors? Are you sure you have the correct sensors? They need to be PNP type for Windstar doors I'm pretty sure. Trying to judge by the pictures, it appears the limit would be the grey cam that has the red and white wire connected - above the board. If its wired how they meant for it to work, it would be like this:
Both (emitter and receiver - even though only receiver wire is actually functional) signal wires from the sensors (not blue, not brown - those are power) would wire to the cam switch. The cam would be adjusted so that it would allow the signal to the board when door is up and keep allowing it through travel down until the door reaches the sensor elevation. At that point, the cam would bypass the signal and the door would continue to close even if the eye was to be blocked. Its dumb.