I’ve read through the thread and not found anything that quite fits the bill. My product is the Whirlpool S20B RSB21-A/G. It was purchased in 2001 and since has had the front and back boards and diffuser replaced (Whirlpool reluctantly covered the cost of the parts after much correspondence) All has been well for two years – but now the fridge is failing to cool adequately – if at all – although the freezer is operating fine. There’s no clicking or other tell tale noises. The internal fan is operating – but the air is clearly not circulating in the fridge.
On inspection today the evaporator was iced up although not terribly – all fins visible – so I guess the frost free widgets aren’t working as they should. Any help and advice to make a decent diagnosis – and so hopefully a lasting cure – would be greatly appreciated.