my fan went off .but it came on and off when i went over bumps  it felt like it was a bad connection. so i went in through the glove box were there was some kind of censor fitted to the top of the duct  Itook it out looked under it and  taped it with a screw driver  it sparked on one of the soldered joints . i soldered it up. job done, it may not be the same problem as yours but its worth knowing
                 chris
                
 May 2008