When did it last blow cool air? I'm sure that you have checked all the switches etc on the dash. Ensure that the belt that spins the compressor is in place. Since you have not mentioned any other problems with the car it probably has it's own belt. If that is in place you may need a mechanic to verify that there is Freon (refrigerant) in the system. Do not go tinkering with that system yourself as repairs can be expensive and releasing refrigerant from the system can be dangerous and illegal. You might also ensure that all your fuses are intact.
Hot air because it is blow out the hot air from the inside of the laptop.
You are low on coolant to the heater core.
Your A/C needs recharged.
your car ac will only blow hot air when there coolannt in the car is finished or the car is oveerheated.
Because something is wrong with it. When it is off it does`nt blow anything, that `s why you only notice it when it is on.
A/C compressor not running
check your coolant level
Why does my Lincoln LS V8 Blow cold air on one side and hot air on the other side
A hair dryer blows hot air out.
it is drawing the hot air off the engine.
check the free on in the compressor and if that's not it you will need a new compressor
the blend door is stuck open