Product review (5 stars): Defrosting again!
My GE top freezer GTS22JBPCRWW friege is once again defrosting perfectly, thanks to replacing the old  fan with this one.  This model of GE , I've found on repair sites, has a fan that tends to wear out after several years.  This is a fairly easy repair if you're at all handy with appliance repairs.
FYI, if your fridge (at least this model) is cooling and freezing normally, and the defrost cycle is running normally, but you've got ice building up in the freezer, including frozen droplets of water hanging from the top of the freezer compartment  and heavy frost buildup on your frozen stuff - it's probably the freezer fan.  The fan is not running fast enough to evaporate the water, which then refreezes.  This is a very reasonably priced fix for an expensive fridge.