How hard can it be?

hi guys need to buy and fit a new heater fan as its pretty cold at the moment and my fan has stoped working,
anyone know how tricky it is and how long it would take to fit?
took it in to a garage when i was having my remap etc done and they quoted me 240 quid,
surly it can be done cheeper then this?
cheers lemon s3 will take it apart in the morning and have a play with the wire.