Pickup cab filters
I believe most of the pickups built in the last 10 or so years have cab air filters, at least my Chevy does. If you haven't changed it you may want to. At 80K miles mine was totally plugged with crop dust, even some soybean straw. I kept wondering why the dash got so dusty so quickly with little use and not being around dust much in the winter. Cost about $17. Under the dash on mine.