Hotpoint Fridge Freezer Model 8595 (frost free) Freezer ok but fridge not working

Can anyone suggest what may be the problem with my F/F? The fridge has stopped cooling down but the freezer works.

Turning the stat up sometimes starts the fan at the rear of the fridge, This would indicate that the stat & the fridge fan work ok. Does the fan blow cold air into the fridge or is this the defrost cycle?

Is there a valve between the freezer & fridge section of the refrigerant tubes controlled by the stats? Some ice does form at the rear of the base of the fridge.

I have read about thermistors causing the problem, if it is that, where are they located & does anyone have the part numbers & a supplier I could use.

Any advice would be greatly appreciated.

need to replace thermistor which is located in freezer compartment behind panel

Thank you Tonto, so it's behind the freezer panel. Is there more than one thermistor there? Would you happen to have a part no & any suggestions where to buy a thermistor & approx cost?