Rear A/C Blower working but no air on 2003 Lincoln Aviator

Rear A/C blower motor located in the back driverside panel sounds like it is blowing but no air coming out of the rear vents? Help, Florida's to hot!!!

Asked by for the 2003 Lincoln Aviator
it may be one of the heating doors which lets the air in the vents.
Where are the "doors" located