The ac started smelling like mildew for a couple of days and now it is blowing regular air.

air filters when used are on the inlet side of the blower motor
that normally puts then behind the glove compartment so the glove box has to be removed to get to them
use a charcoal type filter to help reduce odour.

Sounds like the A/C compressor clutch has overheated and become inoperable. Open the hood, start engine, observe the compressor face. It should be turning and also see if that's where the noise and burning smell is coming from.
Good luck!!!

I have a 2007 kia rondo.Ac was working,parked it for a year,ac wasnt working,recharged,the ac,it worked for a month,an started again,blowing hot ai.If you let it set for hour would start working...then after a few days it would only work early morning,if you dont turn ac of,then it stop working,I see the clutch isnt kicking in,ir you try an put freeon in it soon as you start putting it in it would kick on.An its full of freeon.

it's either low (in spite of your readings) or your a/c clutch is not working correctly or you have too big an air gap in the clutch.
First, just disconnect the 2 pin connector from the a/c pressure cycling swithc and jumper the 2 pins with a wire to force the clutch to stay engaged. See if it blows cold then, and stays engaged. You can run this way for about 15 minutes before you have to pull the plug.
report reulsts.

please don't forget to rate.

This is caused by mold and mildew growing in the moist environment of the AC air ducting and on the Evaporator core, this moisture condenses from the cooling of the air stream. To temporarily cure this problem spray Lysol disinfectant into the Air intake of the system which is in front of the windshield on the passenger side, set the blower speed to high and soak the system with the spray, then let it run a few more seconds and shut it down, this stops the smell for a few months and then it must be repeated.

Hi and welcome to FixYa, I am Kelly. Actually if there is mildew in the system it takes a serious cleaning of the evaporator coil and near by plastic housing / ducting to get rid of the smell. Mildew usually starts forming on the evaporator coil and compartment when the compartment drain gets to be really slow from debris or a dust clog. You can try filters and air fresheners but all they will do is mask the mildew odor. Once the mildew routine starts the only real fix is a serious cleaning of the evaporator coil, compartment and nearby air ducting. Often it takes a good mild and mildew remover to get rid of the problem completely. The evaporator compartment will for sure have to be opened up. If a service shop is going to do the cleaning job correctly they will most likely pump out the freon in the AC system and remove the evaporator coil for proper cleaning. It is not a cheap fix as it is labor intensive and requires the AC system to be drained and re-serviced. Demand that they clean the compartment drain during the cleaning process. My comments are what it really takes to purge the mildew from the AC system correctly. Your call as to fix it or live with it.
Thanks for choosing FixYa,
Kelly

This smell is caused by mold and mildew build up in the AC air passages and on the heater and the AC evaporator cores in the dash, u can spray LYSOL mold and mildew remover into the system at the air intake in front of the windshield with the blower turned to max, use about 1/4 can, then turn off the system and let it sit for an hour, then turn it back on with full heat, let that run to dry out the chemical, this will cure the smell short term until the mold and mildew grow back, it is a fix we did often in the shop, the wetter the climate u live in the worse the problem

When you run your AC, turn if off before you end your trip. You're having it on which builds up mildew. Then when you leave your car there, it stays in the vents. When you turn the car back on, that's the smell you get. Not to mention you should not ever turn your car on with the AC enabled. That's going to cause strain on the initial start of your vehicle that could lead to later complications.

sounds like the system is either low or out of refrigerant. There is a low pressure switch in the system to shut it down in the event of freon loss. First , verify , then test for a freon leak. Once repaired, and recharged, will blow cold air again.

There is no filter, this smell is caused by mold/mildew in the system from normal condensation from the AC evaporator core, you can try Lysol, spray at the air intake in front of the windshield for about 20 seconds, turn of the system and let it set overnight, this will cure the problem for a few months, then you will have to treat it again, as the mold will regrow in the moist environment of the AC air distribution box.