My kenmore Elite refigerator (bottom freezer) has started making a sheet of ice at the bottom that eventually gets so big the door will not close. I have removed thje ice and in about a week, it is there again. I have seen some info saying it might be the drain line is plugged. How do I get to it? What do I do? any other possibilities? Thanks, Dori model 75542

Dori Robinson, June 2010