It started today, and it stops when you push in the "air recirculation" button. Happens with engine off and ignition on. I gather from the net the problem is the air control flap gearbox has stripped. But how do you get to it? From under the bonnet and immediately under the windscreen I can get to the intake and remove the pollen filter (very dirty) and see down the intake past the flap to the (constantly?) turning fan. But how do I get to the stripped gear? There are nuts either side of the intake, but do these drop the whole fan unit inside? Car is a 95 turbo diesel with aircon ... which works but puts a drag on the engine. Thanks for all assistance.