Does anyone know how the ball sensor works?

I have been getting the dreaded LE error and can't get the error to go away. I've tried unplugging the machine many times, tried spinning the drum, even replaced the Hall sensor and no luck. I have a feeling the ball sensor might be the problem but I don't know for sure how its suppose to work so I can't say for sure if that is the problem. Does anyone out there have any ideas?