1994 Ford Ranger Very little air coming out of vents

I removed the cover for the heater core to check to see if the doors that I can access were opening and closing properly. I do believe these are the doors that direct the air flow to the vents, they seemed to be operating correctly, but I do not have a schematic to show me where the other doors are located. As far as the vacuum leaks, there are none that I can find. There are two black vacuum lines farther up under the dashboard, but I can't access them short of removing the entire dash. I listened for any hissing sounds, but none were detected. I do believe there must be another door that I can't see or feel from the bottom of the ductwork that is not opening, but as I said before I do not have any schematics to find it. If you have any idea where it is located I would sure like to have that information or the schematics.
I don't think Chiltons or Hanes manuals have that information.
Thanks so much!

Thanks so much for the diagrams, I know these are hard to find. Now are these for the 94 model? I will go out this weekend and check the vacuum lines leading into the cabin from the engine compartment to see if there are any leaks. I will post my findings as soon as I can. Thanks again for all of your help.