Could be many reasons but the most common would be low on freon due to a leak in the system.
You need to change your thermostat in the car.
If a 1988 Lincoln Town Car is blowing both hot and cold air when the air conditioning is on, there could be a problem with the thermostat. There might also be a problem with the level of refrigerant in the air conditioning pump.
if car is blowing cold air, you need to check the thermostat,the heater core, and the heat control. the coolant will not blow cold air unless there is no coolant at all in engine,then you have bigger problem anyway
faulty control valve on heater or air in the lines
Low coolant and a clogged heater core are possibilities.
Is the AC condenser in your system blowing cold air?
When the car is off. sounds like a short in the blower or short in the wires
Car not blowing air or heat
Have you checked your thermostat?
because you car is stupid
There are several possible reasons why the heat in your car may be blowing cold air instead of warm air. It could be due to a malfunctioning thermostat, low coolant levels, a faulty heater core, or a problem with the blend door. It is recommended to have a professional mechanic diagnose and repair the issue.
needs heater core replaced wost likely be hind the glove box