Thats cool, please tell me what that plug is for.. I've always wondered but never bothered to look in the book to see what it means.. AHHHAA
The blend door is actually the part that controls the temperature by moderating a door position that mixes cool air from the evaporator and warm air from the heater core. For recirculate vs fresh there is a different door that goes one way or the other to either direct incoming air from outside (fresh) or from inside (recirc). This door can be either mechanically operated by cable, or vacuum operated. It will be somewhere near the blower motor on the intake side, upstream generally in the area behind the glovebox.
The blend door is actually the part that controls the temperature by moderating a door position that mixes cool air from the evaporator and warm air from the heater core. For recirculate vs fresh there is a different door that goes one way or the other to either direct incoming air from outside (fresh) or from inside (recirc). This door can be either mechanically operated by cable, or vacuum operated. It will be somewhere near the blower motor on the intake side, upstream generally in the area behind the glovebox.