RichieST you were spot on with the pollen filter judgement. Take a look at the pic below of the dirty pollen filter. Looks like they've never changed it despite having a full Ford Dealer service history. Took it out, replaced it an nearly blew my eyebrows off.



I remember taking it to them for a major service twice and still having a blower problem. Guess they don't change pollen filters as a regular service item. Haynes states every year or 12500.

At least anyone else with this problem will hopefully find this thread helpful.