A periodic maintenance item for any vehicle is to replace the cabin air filter, for the dash AC.
I must admit, I thought our coach didn’t have a replaceable filter, until pointed out on my Tiffin Allegro Bus 2016-2018 Owners Facebook group. Oops.
Here’s a picture of where it is located in the generator compartment, for context:
It’s rather difficult to get out:
Ours was definitely overdue for replacement:
