Why does my A/C smell musty?

There could be mold on the condenser coil or drip pan. Here's a link with more information:

https://dengarden.com/appliances/how-to-remove-that-bad-mildew-smell-from-a-window-air-conditioner

I agree. The condenser coils need to be cleaned and check the drip pan. The coil on the side that isn't pushing air may also be restricted.

Here's great instructions I have used:

https://youtu.be/_M-JLzIQHtk

If the filters have gotten wet, it may smell musty. I would make a bucket of warm water with a squirt of Dawn dish soap and a tablespoon of vinegar. I would use this mixture with an old toothbrush and scrub every inch of it. If it's a window unit, it could be pulling the smell from outside. Either way, I would give it a good scrubbing anyway.

You should probably have a "tune up" done on the unit. Around here, they run specials that are $49-$89 and include cleaning. That would also let you know if there are any issues to look for.

Go to Youtube and look for info on that model.

Call the manufacturer with the make and model numbers, they have people who can help you troubles shoot the problems with that unit. They know their product and have technicians who can support you on the best way to proceed.

Yes, I agree about a tune-up. You should get your HVAC checked every year.

Maybe you can put a fresh dryer sheet next to the filter.

I have a portable unit. Mine has a tank to collect moisture. There may be some mold in the tank that needs to be cleaned out. Check owner's manual or go to website.

Hello. I would suggest contacting the manufacturer on the telephone to see if there’s any other further maintenance issue that you need to be take care of if you do not have a manual available.

Hi Joanne, hope this helps you out,

https://www.youtube.com/watch?v=XIwMIMKq7Ec

Here are some ideas on why it may smell: https://www.youtube.com/watch?v=GryJOmUJVZI

https://dengarden.com/appliances/how-to-remove-that-bad-mildew-smell-from-a-window-air-conditioner

Your filters could need cleaning.

Have you changed the filter?

WOW thanks all for the suggestions, I did clean both filters. it seemed to help a bit. Now the air only seems to come from one side also most of the buttons don't work. I can't change the fan setting, etc., I think I will just get a new one for next year

Hi Joanne, hope this helps you out,

https://hvactrainingshop.com/portable-air-conditioner-musty-smells/