2001 Explorer Air Vent Problem

I have a 2001 Explorer Sport. The air vents seem to have a leak. Above 30 mph, even with all climate control turned off, alot of air is coming through the vents and makes a terrible whistling noise. At highway speeds this is most annoying. Does anyone know how to fix this problem? I would appreciate any help that anyone can provide.

Thanks in advance

I also have an issue like this with a '96 Explorer. After getting ac work done, I had the dealer service man ride with me. It was cool out and he could feel the air coming in with access thru the glove box. He was quick to ask if it whistled, a common problem on '01 he said, so I would bet the door is just not closing tight.