This is very confusing. Ever since I left my car sitting for 1 month to go to Seattle, my car has been making a loud weird sound when I blow my A/C. This sound is loudest in the glove box area and under it. When I drive my car, it accelerates slower and the temperature gauge gets closer to the H. What's wrong and what should I do to fix it? Also, someone hit my front bumber on the front corner and exchanged paint. How do I remove the paint scratch marks? I heard reducer is ok. Thanks! Here is a video of the problem!

 

Your video doesnt play.

And you need to see if the fans are coming on. Both should come on together.

 

It sounds like the hiss of a low refrigerant level or un-cooled refrigerant entering the evaporator. Does the sound change when the blower speed is changed? Is this a V6 or 4 cylinder? When you turn the A/C off does the sound go away?

Check the engine coolant level, and the fuses for the radiator and condenser fans. A lot of vehicles that are parked for an extended period of time can result in fan seizures, blowing the related fuse first. Do not operate the A/C until you can solve the overheating problem and/or fan problem first.