You might need a new thermostat or heater core.
Lincoln put a thermal switch in the hoses that run to the heater core in cars of this age. This switch would not allow the blower motor to run until the coolant was warm. This was a "luxury" feature to keep the heater from blowing cold air on your feet. After a few years these switchs would go bad. This could be your problem. I have replaced mine once and I'm looking into a way to bypass it. You can just use the vent function with heat to keep warm until you replace the switch, that's what I'm doing for now. I believe the switch runs about $50 from FoMoCo. You could also have the problems listed in the other answer.my Lincoln town car doesn't have the switch in the heater hose , now where do i look i have good AC but no hot air , where is the vac moter for the heater to outside air switch located ??1994 a breed by its self ?? ill just bet