Bongo Fury

I've owned my bongo for just over six months now the aircon all works ok very cold. Now the cold weather is upon us
i've noticed that when i push the windsreen defrost button the warm air does not come out of the top dash vents.
It only seems to come out of the vents lower down.
My van is a 1999 with climate.
Help please.

Uncoupled servo to the flaps..? Mines manual but the principle is similar in my book!

Have a look at this thread, its the most common cause of problems http://www.igmaynard.co.uk/bongo/forum/ ... =3&t=26835

Thanks for the help all done.