What your ac is blowing warm air?

Several things can cause this:

1. Your compressor quit working so you have no cooling
2. It is so hot that the AC can't pump enough energy out of the air to cool it down below a temperature you consider "warm".
3. You have lost some coolant so the system is being inefficient
4. You have formed ice on the coils which prevents air flow over them to cool the air as efficiently as it would if it could flow over the finds that are covered by the ice - note that this often occurs when #3 above happens.
5. You have a leak in your AC ductwork that is allowing the cool air to mix with hot air
6. The AC has just come on and has not yet managed to establish low enough temperature s in the coils to cool the air yet.

Any one of these - or a combination of two or more - can cause the AC to blow warm air.