AC not working

I have a 2002 TB with 77,000 km on it, yesterday my AC worked fine and today it is not cooling the air down it is just blowing the air out at the same temp that it went in. I let it run for a while and there was no difference. Any suggestions

No quick ansewer here, someone has to see if the compressor engages, check ac pressures also. Ac pressure switches were troublesome in these years, but a diagnosis is the only way to proceed here.