Recently my tenants informed me that their refrigerator freezer is not freezing even at the coldest temperature setting.

I went over and checked it out. The compressor runs, the evaporator fan runs, door seals, etc. I checked the compressor and it was warm. I unplugged the refrigerator and checked the start capacitor with my Fluke DVM. I also checked the compressors 3 pins and got resistance on each pin. I took the back panel off the freezer and checked the thermostat both cold and warm and it works. I checked the defrost wire and got resistance so it works. I checked the defrost timer as best I could figure out it works.

The coils in the freezer do get a bit of frost on them near the connections but the rest of the tube is not that warm.

I would guess that the refrigerator slowly lost refrigerant over the years and that it is time for a new one.

Any advice would be appreciated. Thanks!