Easy, but a bit fiddly. 30 minute job if you do it on a regular basis, but set aside 1-2 hours for a first time.
I think its in the same place as the E39 more or less, so access is by removing the cover under in the footwell on the drivers side (the big one that hides the pedal box, under the steering wheel area)
You may also need to remove a piece of carpet trim from the transmission tunnel as well. (Careful not to lose the screws).
The FSR/Hedgehog is in a tight corner near the clutch pedal (or footrest for auto's), behind the heater control panel. It has one electrical connection, and its clipped in (I think with spring clips, no screws).
Its not a coded part, so just unplug, slide it out, and you'll see the heatsink which gives it the nickname hedgehog. Slide in the replacement (Should be between £45-70 depending on where you source it) plug in, and reassemble interior.
You'll need a Phillips screwdriver (actually its probably pozidrive, but in sure some can correct me on that). and a torch is handy so you can see what your doing. In the E39 there's also a ribbon cable close by, Im not sure if the X5 has that, but if you see a ribbon, just be careful, its hard to replace if you damage it
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If your car has its original hedgehog, you may notice the new one is a different shape. BMW tried several different version. I think they improved it a little, but they still break from time to time.
There are several video's on youtube, but most of them show the left hand drive cars.. Its not much different on our cars though, just on the LHD cars the part is actually on the passenger side instead, so there is a little less "in the way".
If you can use a screwdriver though its certainly a DIY job.. BMW dealers would probably charge you £500 for "diagnostics", try changing a dozen parts, and then charge you for the whole lot, unless you specifically ask them (or an INDY) to change the FSR.... It can be called FSU (final stage unit), FSR(Final stage resistor), Parts dept often call it blower resistor, and DIY/Owners nickname it the hedgehog.
Anyway. Hope that helps, and you get it sorted
