If your saying the ac blows air but it isn't cool, I'd have to check the compressor clutch, see if it is engaged. If it isn't engaged, I'd check the circuits at the ac relay, two of those terminals should be hot with key on. The pcm grounds the coil side of relay in order to energize. The pcm has to receive an ac request before it will energize the relay. If your low on refrigerant, the pcm may not receive a request.