Easy one, Fan RHEOSTAT. Located on the blower unit itself behind and under glovebox. £30 from the dealer. Held in the unit with 2 phillips screws and the plug with i think 5 wires. The air from the fan blows over it to cool it but as mine has done a while back, eventually burns out. All it is is a series of printed tracks that have different resistances.
jeff, December 2007