freezer not freezing

Hi. How is your air flow? Are you getting air flow through the vent over to the FF side? Does the unit have a defrost issue? Sounds like a defrost issue or sealed system issue. This could also be a dirty condenser causing the compressor to over heat. Make sure the coils are clean. Does the mullion feel hot to the touch? You could have a condenser fan motor that is not rotating at high speed. The condenser fan motor will rotate at different speeds depending on how hot the compressor is. I have found faulty control boards that cause the fan to spin at a slow speed when it should be spinning at a high speed. You will find the compressor and surrounding areas are very hot if this is the case. If everything is running, you have good air flow, and the compressor is not overheating, you must have a sealed system issue.