Product review (5 stars): Easy fix, great price!
My freezer portion of my refrigerator/freezer kept freezing up in one solid piece of ice.  I replaced the heater element (product number WR51X1005) and the thermostat (this product) for less than $50 total and the problem is solved.  I was expecting aa service repair person to charge me nearly $1,000 had I used them instead.  Try this first; it's easy, effective, and if your coils are freezing up; this is likely your problem.  Tip: Remove the old one, use a continuity tester.  If the heater is not continuous, then it needs to be replaced.  Simple.