You have to get it recharged. you have no freeon left which makes the cold air
You might need freon
It's out of freon or refrigerant.
Your A/C needs recharged.
Probably leaking freon.
A.C. circulates air(just like a fan) and turns it cool.
the function is to blow the hot air from outside to cool air in side
absolutely because if the compressor is not engaged then it can not produce cold air.
Compressor not running, blown fuse, low of freon.
You are low on coolant to the heater core.
The most common cause would be low refrigerant.
That can happen if they are low on freon.
a leak