Ok, we need more information. Do you have a wiring diagram? I'm new here, I don't know if there is a wiring diagram on this site. Check your fuse box. Any fuses that are part of the a/c system should be marked a/c. You should be able to tell by looking at the fuse to see if it is blown without removing it. You can also check it with a volt ohm meter. There are probably at least 2 fuses. One for the fans and one for the compressor clutch.
Can you see your a/c compressor? If you can, it has an electric clutch in the center of the pulley. The pulley is on a roller or ball bearing and free wheels if the clutch is not energized. The center section of the pulley is the clutch. See if you can rotate the clutch. If the center part will not turn, the compressor is frozen, and needs replaced. Look at your refrigeration lines. Freon is an oil magnate, if a line develops a leak, it will be oily. If you find oil on a line, clean it off, and start the engine to see if the oil comes back. If the compressor does not even energize the clutch, it may be completely out of Freon. If the clutch energizes, does it short cycle (energize/deenergize/reenergize rapidly). If it does, it may be low on Freon. If you have not used your a/c or defroster in a few months, the oil may have dropped off the shaft seal into the compressor sump and since oil makes the seal, you may have lost your charge. If the seal has worn, you may have a leak at the shaft seal.
You have safety switches in the a/c system. Those switches will shut deenergize the compressor clutch if the Freon pressure goes too high or too low. When you get the short cycling that I referenced in the previous paragraph, it is because the unit is low on Freon and the compressor is cycling on the low pressure switch.
I hope this helps. To do any sort of real trouble shooting on the a/c, you need a set of refrigeration gages. If it is low on Freon, you need to leak check it. If you find a leak and repair it, you will need a vacuum pump to pull all of the air out of the system. Also if you open the system, you will need a new receiver drier.
I just thought of something else. Was you system set on max when it quit working? Have you tried it since? A/c systems are not designed to be refrigeration systems. I have seen evaporators ice up, that is build up ice like your refrigerator. when that happens, you lose airflow over the evaporator coil. Your system is not designed to have a defrost cycle on the a/c. If you turn the system even colder when it ices up, it gets worse. If the ice build up is too bad, the suction pressure will drop, and the low pressure cutout will deenergize the compressor clutch. If the a/c unit has not been used in a while, the ice will have melted off, and it should work. If there is moisture in your system 1 drop of water freezing in the expansion valve will shut down your a/c system! That is why it is essential to change the receiver drier any time the system is opened.
I probably gave you too much information. I'm a retired transport refrigeration mechanic, so I know quite a bit about automotive a/c systems. If nothing else, this answer should tell you that saying my a/c doesn't work and asking for help on a board and hoping to get useful information is probably not possible. To get your a/c repaired, don't take it to the dealer unless it is under warranty. Find an automotive air conditioning specialty shop. I've seen dealers change out a compressor because it froze up and send the customer on his way. In a week or two after the warranty is off, the compressor fails and they sell the customer another compressor which lasts until a week or two after the warranty expires on that compressor. If the compressor fails while under warranty, they replace it but you don't get a new warranty, so when that new compressor fails, the customer is "on the hook" for another compressor.
If a new compressor is needed a reputable a/c shop will clean out you system including replacing your expansion valve or orifice (depending on what type of system the manufacturer installed in your car). They will replace your receiver drier anytime they need to open the system. As well as leak checking the system and replacing any leaking components, before they recharge your system. If the leak is in your compressor's shaft seal, they may replace the seal or they may replace the compressor. Often the labor to replace the seal is more than the price of a compressor.