1991 Dodge Ram Van B250 Q&A

1991 Dodge Ram Van B250 Question: blower fan does not put out air

I changed the switch, fan motoer and resistor. Now it blows on low and you can hear the fan increasing speed but the air flow out the vents does not increase. Where is the air door located and how does it operate? (vacum, cable or elec?) -
Answer 1
You have three (3) Vacuum operated doors in the HVAC housing. The Blend Air Door (Temp control), the Mode Door (Defrost, Vent, Floor, Bi-level) and the Recirculation Door (outside air.recir air). Any obstructions to the air inlet (RECIRCULATING AIR DOOR ) will prevent air flow in, thus no air flow out. -
Comment 1
This I know what I don't know is where the "recirculation door" is located. I know where the Blend and Mode door vacum Diaphragms are. but don't see the outside air door vacum diaphragm. Is it inside the box under the hood? -