Tried searching for this and while there was a thread on it there was no conclusive answer.

I was cleaning out debris from my blower motor and noticed above it that there are 2 foam panels that I'm assuming open/close to regulate air flow throughout the cabin. Does anyone know the name of this part or the part number, or how to remove them so I can clean the old foam off and replace it with new foam? Not only does it probably not seal very well anymore, it's deteriorating from age and it falls directly in to the blower motor. There are 2 Phillips screws per panel, but removing them does not free up the panel

 

I don’t think it’s a filter, it’s just foam glued to the two metal doors. I have a blower unit that I pulled from
a parts truck and I can take a picture of you want.