I have had yearly frost buildup problems since I bought this freezer. It was supposed to be a manual defrost model, so I knew that going into the purchase.

Today the vents and evaporator were again completely frosted over so I began the process again with my heat gun and space heater.

While working on it I noticed what there was what appeared to be a heating element running along the bottom of the evaporator with heavier gauge wire attached to it. I also saw what appears to be a small black object clipped onto the upper coil on the right. Does this mean my freezer really is self-defrosting? Or is it nonfunctional even though everything is plugged in? A parts diagram I found for my model says it is a heater element, but in my case evidently not doing it's job.

I would appreciate any advice I can get on this. If it is supposed to defrost on its own, I would gladly buy the replacement part for $71.00.