99 Explorer Air Conditioning Problem

I have a 99 explorer and when you start it up the air blows great, but after you drive it for a while the air almost stops blowing out of the vents and it makes a very loud blowing noise behind the glove box? Any ideas?

Sounds like you either have a blend door issue, or possibly something in the blower motor squirrel cage or housing.

Does your Explorer have the automatic temperature control panel or manual controls?

-Rod

It has the manual controls

where is the blend door located and how does it work?