Hall Sensor Diagnostic
It's really pretty easy to diagnose a Hall effect sensor. If you plug the sensor into the board (so it has power), then wave a metal object (screwdriver tip should work nicely) very close to the head of the sensor, the light should go on if it's reading. If the light doesn't come on, there's an issue. An issue would most likely be the wiring. You may want to test the same sensor by plugging it into a known good port on your main board. Any of the axis stops should behave the same, but since it's both the x- and y-axis sensors which are not functioning, I'd try attaching them to the z-axis stop.