I also have a problem with my heating! I have an '05 T5 1.9tdi, and I am getting no air at all coming through on 3 of the 4 dash vents when the dial is on face only. On one of the dash vents I get very slight air but does not feel as much as it should.
When the dial is on feet, or feet and windscreen, or just windscreen, the heating works perfectly, but just not on the face pointing dash vents.
Any suggestions would be greatly appreciated. Thanks, Andy.