I have a kenmore frostless freezer model number FFFH20F2QWC and it worked well for months after I got it (used from a "repair" shop) past the "warranty" date they gave, then it quit. everything I read pointed to the thermostat heater so we checked it (i think i did it right ) and it had no power so we replaced it. about a week to wk and a half later it stopped cooling again and the temp light was blinking and beeping again. I really like this freezer but can't keep replacing the heater or leaving it unplugged for a while as to reset it every time it does this. Any suggestions?