Hotpoint Mistral FF92 – Fridge not cooling

I’ve searched on this topic and it seems that this may well have been covered in a now deleted thread. Anyhow, we first had this problem a few weeks ago – freezer fine, fridge heating up to room temperature. I rang a friend of a friend who’s a refrigeration engineer and he advised us to defrost completely as ice may have built up in the duct betwee the two compartments (or at least that was my understanding). We did that and the fridge returned to the correct temperature for a few days before starting to heat up again, it’s now at +22!

Spoke to the Engineer again and he came to have a look. He took the back panel off the freezer and tested a couple of bits and said it could be one of three components that needed replacing, but couldn’t tell which so we had to replace all three. He said he’d be in touch with a price. That was over a week ago now and I can’t get hold of him! And because he’s done this for free so far, I don’t feel good chasing him up all the time. Anyway, I thought I’d see if there was anything I can do myself.

I’ve found the link to the two thermistor components and saw a comment somewhere else that said it was relatively easy to change them, but I wondered if someone could please confirm:

a) if these components are (probably) the right cure for our problem
b) where specific instructions can be found for how to change them (am reasonably handy!)
c) what to do if these don’t cure it!

Thanks in advance for your help. It’s not massively urgent as we still have our 15 old fridge freezer (a Lec) in the garage, still chugging away with no problems….but it is a pain in the ar$e not having one indoors (no door through either, as wife consistently points out 😆 ).

Have also resolved to check for problems with specific appliances BEFORE buying them in future! :rolls:

Colin