Citroen Xsara 1.9 D of 1997 Spraws problems

Good night to everyone I have a Citroen Xsara from 1997 the air conditioning works well, the air of the cabin's air I have put new, I have a problem
I do not make the air through the area above the dashboard, I have checked the motor the reducer that opens the cold and the heat works well the traps What is closed?
I would very much appreciate your opinion
thank you very much