This appears to be a reference to the defrosting component of a Amana freezer. Let's just assume that it is not a problem with the freezer door seals. (If the seal is not a tight seal when the door is closed, you have melting occurring and the the freezer trying to compensate by refreezing, yielding a lot of icing in the compartment. This is what happens if you over stuff the freezer and the freezer door does not quite close firmly, as well.)
The Amana defrost thermostat might be defective or have become dislodged for some reason. If defective, it would require replacement. But let's say it is not defective. The defroster didn't work when there was too much ice buildup. This could cause the molex connector in the thermostat to contract, breaking the connect activating it. One user "fixed" this problem by putting aluminum foil inside the molex connector.
If the theromostate became dislodged from its "attachment point", one would need to know the model of the freezer know where that point was. https://www.applianceblog.com/mainforums/threads/amana-defrost-thermostat-installation-location.27405/
There are videos describing replacement of the thermostat in some Amana's. You can find such on YouTube. I just can't promise that replacement would fix the problem.