Evaporator not fully defrosting--freezes up every couple of months. What triggers defrost cycle on these electronic controls--what controls duration of defrost cycle---bimetal sensor on evaporator? Can I extend heat from calrod by gently wrapping 12gauge copper wire and extending it further up evaporator? Had to add additional heat strip on previous GE model with the same problem. No vents are blocked. More info on evaporator fan upgrade?

wayne hudson, July 2009