Hotpoint Mistral 8595 fridge freezer too warm

Re: Hotpoint Mistral 8595 fridge freezer too warm

Cerisehippo wrote:Hi,
My Hotpoint Mistral 8596 fridge freezer is too warm. I took off the bottom and hoovered the grills (amazing amounts of fluff) and left it to defrost for 48 hours. The freezer is now cooler -9 and the fridge is cooler +12 but not cool enough. The temperature warning symbol is shown but no error codes. Everything sounds normal.
The fan at the top of the freezer is working and was continuously on while the freezer was at room temperature. I took off the cover in the top of the fridge and saw the green thermistor but it goes straight into the insulation with no connector block.

Close up of where wire goes into insulation

This shows the top of the freezer, the fan and another green wire (is this a thermistor?)

This rubbish photo shows behind the freezer back at the bottom.

Not sure what to do now.
How do I access the yellow thermistor? I couldn’t find one.
Is it likely to be the fridge or freezer thermistor that is wrong?
How to I change the green one if there is no connector block?
Does anyone have a service manual?
It has had a thermistor replaced in the past by an engineer and worked fine again. Strangely there is a lead parcel taped to the back of the fridge leading into the compressor area which looks like it was a later addition.
Its a great huge fridge freezer and I’d like to fix it but it is more than 10 years old and not worth a Hotpoint fixed price service charge!
I can just about use a multimeter and any help getting this working again would be appreciated! I hate to chuck out things that can be fixed.