C5 2009 heating & aircon system

[Superaquarama]

Hi Guys,

Having had a bad sinus problem a few years ago and having no wish to have it again, wife is hypersensitive to air vents & draughts. On the C5 there is a small amount of air coming out of the 'soft' aircon vent on top of the dash all the time, likewise the side window demisters, which 99% of us would never even notice.

There is a rotating knob by the vent to control this in theory, but it doesn't actually seem to make much difference. According to the handbook, no air should be coming out of the vent, nor the side window demister vents, unless the button is set to the screen position. It's a dual zone system, by the way, with separate controls fore each side.

So the questions are:

a) could the rotating knob be disconnected and thus not shutting off air ?
b) can the flow / distribution be adjusted with the diagnostics ?
c) any point in taking it to the dealer ?
d) or should we just resort to gaffer tape ?!

Be grateful for any assistance.

[Superaquarama]

Just refreshing this post as we weren't exactly overwhelmed by replies !