Product review (5 stars): The solution after all these years
My Kenmore refrigerator defrost drain started having problems about 2 years after I bought it. It varied between ice dams in the freezer or water collecting under the crispers in the refrigerator, or both.  Three times I had a repairman come out and clear the drain.  On the 3rd trip, the repairman put a piece of wire (think clothes hanger) down the drain and connected it to the defrost heater.  He must not have made a good enough connection, as it still froze over.

Being tired of paying someone else to do it, I watched and made note of how the repairman removed the freezer back panel as it had some hidden screws and connections and I did not want to break anything by forcing it.

I removed the ice dam myself and made sure the drain was clear by using hot water and could hear it drain.

I purchased this heat probe from Amazon, installed it securely, and haven't had a problem since I installed it 3 weeks ago!  I'll update this review in a few months IF I have any problems.

So, don't waste your money on a repairman, because A)It's $65 to $100 each trip and B) he/she likely is not going to permanently fix the issue.

Get rid of all of the ice, install this heat probe securely, and you should never have to worry about ice or water collecting again.
6/29/13 update: Still working perfectly