How do you get your auto parts without telling the guy helping you the Make, Model, and year of your vehicle?
We really need to know what brand air conditioner you have, but with the year/brand/model information some other owners reading this might know from THEIR rig what brand/model of air conditioner you have.
Your picture isn't a recognizable RV air conditioning intake vent to me. I have been on tis forum over 12 years, have answered over 5000 posts, and have never heard of your problem, as you describe it. Knowing a typical rooftop RV air conditioner's layout/functioning, I would think that the main fan motor would have to be running backwards to do what you described.
Maybe you need to call a mobile RV tech.