My aircon is not working, the econ light does not go out when you select auto therefore the aircon does not work. I think it started when the alternator pully was replaced can anyone give me an idea what is causing this and how it can be repaired

 

If the ECON button stays illuminated it means the A/C is inoperable. There is a major fault in the air conditioning management or there is a leak in the refrigerant system. You need to take it to the dealer or a qualified A/C repair shop that is familiar with audis.