I've had two evaporator fans burn out on this fridge over the past several years. The most recent one lasted less than a year and a half.

I've noticed ice build-up in the vent between the freezer and the fridge section, so I'm starting to think my REAL problem is in the defroster. Ice build-up leads to warm fridge leads to fan running continuously leads to fan burning out. Does this make sense? Would the problem more likely be in the control unit or the heater wire? (Or am I going down the wrong path entirely?)