I have a GE SxS 4 years old that once a month keeps frezing up. I have already changed the board. Heater ohms out fine and so does the defrost thermastate, Just in case I changed the tremastat anyway. It's defently acting as a defrost issue. Could the little sensors (not sure the name) in the frezer be doing this, because I have seen that plenty of times, but it frezees back up in days not weeks. Sory I don't have a model number but its just your standered SxS. Thanks in advance

There is such a thing as "intermittant" fan failure. When evap fan runs for "x" long and gets hot, it stops spinning and causes ice buildup on evap. can try lube- i use dielectric type. When compressor runs, periodically check freezer evap fan to see if running also.