Why is the green light flashing on your whirlpool dishwasher and its stopped working?

Haven't got a Whirlpool Dishwasher but have had several other types and in one respect they all did the same thing. Namely, on completion of the pre-wash, wash, rinse and dry cycles a green flashing light appeared to inform the user that the dishwashing process was complete and within a few minutes the load could be emptied.