To fix your freezer not freezing you should first find out why it's not freezing.
Check the temperature settings and gaskets and also be sure the condenser coils are clean and the frost buildup is gone.
Be sure the freezer is not too full either as it can prevent the freezer from circulating the cold air.
If the freezer is a deep freezer or standalone freezer and it's not freezing it could be low on refrigerant due to a refrigerant leak.
When your freezer is not freezing but your fridge is fine then it can be that the freezer needs to be defrosted or the fridge seals are bad.
Other things that can cause a freezer to not freeze but the fridge to work are a faulty defrost heater located beneath the evap unit, blocked drain from under the evap unit to the evap pan beneath the compartments, faulty defrost sensor, faulty control board. If the evap unit is cold but the fan is not operating then it may be a faulty fan or fan power supply from the control board.
And if the freezer is stuffed too full then it can prevent the cold air from circulating properly and cause the freezer to not freeze the food properly.
The signs that your freezer is not freezing is foods are not freezing solid or the temperature of the freezer is not getting below 10 F or is staying warm.
Other signs that your freezer is not freezing include.
Your food is spoiling. Just like fresh food, frozen food has a shelf life, which typically ranges from about two months for cured or processed meat to a year or more for fruits and vegetables.
Frost is building up on the freezer walls.
Your freezer is making noise.
The temperature a freezer should be set at is 0 F degrees to keep the food frozen and safe.
A freezer should be cold enough so that frozen food is kept frozen to prevent spoilage and bacteria from growing.
Most freezers should be kept between 0 F and 5 F degrees; refrigerators, between 38 F and 42 F degrees.
If both of these settings are only 10 F degrees lower, you could be using up to 25 percent more energy.
For example if ice cream gets soft at the recommended settings, your freezer may need servicing.
When the freezer is too cold, the defrost heater may malfunction.
Once this piece of equipment stops working properly, the freezer can no longer prevent frost from accumulating.
A broken or improperly functioning defrost heater will lead to other problems.
Some signs that your freezer is struggling to work include excessive frost, a loud motor sound, ice at the bottom of the freezer and freezer burn on the products.
Other signs that your freezer is failing or going bad include.
Your food is spoiling. Just like fresh food, frozen food has a shelf life, which typically ranges from about two months for cured or processed meat to a year or more for fruits and vegetables.
Frost is building up on the freezer walls.
Your freezer is making noise.
If the environment is too cold, the freezer may not get sufficient run time to maintain its temperature.
If the temperature is too warm, the appliance will have a hard time getting the interior down to the desired temperature.
Dirty condenser coils or a broken fan motor can also cause insufficient freezing.