My defrost heater is staying on, melting everything in the freezer (and some of the freezer parts!). This is "fixed" from the previous problem which was the freezer icing over. To fix the previous issue I replaced the two thermostats with a new thermostat. Things seemed to work for a while but the freezer has had melting issues. I opened the unit and the freezer was hot. Hot enough to melt a foam air director. I figured that the board with the timer was toast so I replaced it, but it is still doing the same thing.

The thermostats are listed as the same part so I am not sure why there were two of them. I am also not sure what controls the defrost cycle, some units have temperature feedback or a "too hot" thermostat but this fridge doesn't seem to have either.

I bet this is a simple fix, but I sure can't figure it out.

Thanks for the help. I don't think this fridge has a defrost high limit thermostat. The parts diagram show two thermostats of the same pn and they are, at least they are now since I replaced them, the type that let's the defrost heater turn on if the coils are cold enough. I can't find a schematic or an operational description to help me figure it out. Maybe I will just order up two more and put them in to see what happens. It could be I got the wrong replacement part.