1999 1/2 Jetta TDI Air Cond question

I have a 1999 1/2 Jetta TDI, (same body up to 2005) and I was wondering if anyone else has had this strange occurence. When i run my air conditioning, the air flows freely through whatever channel I choose, be it the vents, defrost or at my feet. But after 20-30 minutes, the fan is still blowing cold air, but it's not comng out of anything on the selector dial. I can feel the air coming out of cracks here and there, but not out of the vents, defrost or at my feet. :screwy: :banghead:

Now, if I turn off the A/C, in about 2 minutes, it starts to come out like normal...anyone ever have this problem?

Thanks.

Serge

does the cable on the vent position turns smoothly or gets tight to turn? train of tought is the flaps which the cable pull may be loose. some telltale signs are the rotary knobs are hard to turn