Scrappydoo13

Hi all! The heater fan on my 2003 blobeye hasent worked since I got her and now with the cold weather in full force i need to fix it! I have checked the fuses (all ok)and checked to see if the fan is getting power (it is) so i was wonder if i buy a new/second hand heater/fan unit is it am easy fit and has anyone done it before that could give some advice??