You sure its the fan not a fuse or crap wiring, if not its def new fan jobbie
If it is the fan they are easy to get to mate just need to remove parts to get to it.
Its behind the removable section of the bulk head! so if you look at your inlet the black panel behind that can be removed in two sections using philips screw driver on the few screws in the corners holding it on. Once you have removed this you will see the fan there in front of you. un-clip the two wires and undo the two 13mm bolts holding it in and it will slide straight out.
I tried finding a picture as that panel was removed on my si to show you what it looks like but this is the best i can find sorry its not clear.
If you look at my red power lead running up the back you will see a black box in the middle...that your fan mate

Hope this helps