We have a Kenmore fridge (15 years old) with the freezer on top. The freezer is having a problem where the drain (I presume for when it defrosts) keeps filling with ice and then the entire bottom of the freezer fills with ice and begins dripping water into the fridge below. (similar to this question) We have defrosted and cleared the drain and the problem persists. We are to the point were we need to deice the drain nearly every week or water starts to drain to the fridge section. What are we missing for a more permanent solution?