the a/c is blowing warm air where to start to diagnose the problem ?

 

have u checked the freeon?

 

Yup probably needs some freeon, you can get kits to do it yourself from autozone for like $30 i think.

 

If it suddenly just stopped working do not just buy the refrigerant. They sell some stuff with a UV dye in it which with a black light or yellow glasses you will be able to find a leak. More than likely if it just stopped working you have a leak.

Does the air coming out smell? Sounds funny, but does it? Could be a different problem. Believe me I just went through and ended up having to replace the evaporator core. Got very cold AC now, but at a $890 price tag.