hotpoint ffm90 not maintaining temp

[lushy0709]

hi all i am a noob on here
please can someone help as i have tried everything i can think of.
fridge/freezer does not maintain temp freezer around -8 and fridge +5. transfer fan in freezer behind panel at back does not turn (does this start after freezer reaches certain temp?)
things i have tried:
1. removed freezer panel and defrosted checked all vents are not blocked.
2. listened for compressor this is fine and the pipes in freezer start to freeze.
3. turned off for 24 hours restarted
4. checked connections.
5. checked what i believe to be thermal fuse four wires 2 blue 2 brown with a continuity test
any help on this will be much appreciated.

[tonto33]

need to replace thermistors on this one

[lushy0709]

need to replace thermistors on this one

hi many thanks sorry to be a pain but where are they? what do they look like? and where can i get them from?

[tonto33]

mmm sorry my mistake just double checked the model number you need to change thermal fuse.http://www.partmaster.co.uk/cgi-bin/...0%20thermistor and defrost element,http://www.partmaster.co.uk/cgi-bin/...0%20thermistor