2002 Ford Taurus very little heat from heater

Getting very little heat from heater or defroster. Cooling system is fine and heater hoses going through firewall are very hot, pleanty hot to produce heat. Suspect a control door inside heater, but am not familiar with how they are arranged. The one door i can find seems to be working but cant be sure unless i remove a rather large plate from the heater unit inside the car. The air conditioner seems to work good.


thanks
Sonnyd3