Ford: automatic climate control, automatic climate control, 1989 lincoln towncar

Question
I have a 1989 Lincoln Towncar with automatic climate control, and I get little to no heat from it. The radiator, heater core and thermostat has been change. And still very little warm air. What else can be changed to correct this problem?
Thanks for your help.

Answer
KJ  temp dlend door actuator is inop. drop your glove box and if you look to the left a little on top of your evapator case you will see a black square box with wires this is the controler move the temp from hot to cold and see if you can see it moving if it does and then the door is broken if not the replace the actuator.