I looked it up on Mitchel on Demand but can't find where the Cabin filter is located, I quickly looked under the hood, and near the fan motor....My glove box codes say I have one, any ideas??

There's a screen on the blower motor for the a/c, but I'm not sure of anyothers.

I've not found one either. Ford has one in it's Taurus body, when it plugs up, the car fogs up!! Found this at work in the company fleet vehicles.

On a similiar thought, why not filter the air the truck pulls in?
When I get behind a gasser with a bad burn it fills the cabin with fumes as the air intake for the a/c is bringing them in. Happens alot in the country but almost never in the city but the flip side of that is the air quality in the city is hardly breathable most days due to ozone levels. I would llike to add an ionizer and a particulate filter just for the fresh air side of the a/c.

QM, me too! I hate the headache, etc. feeling when driving behind a poorly tuned gasser. The diesel is OK, within reason. With a big block Furd, it doesn't matter if it's tuned or not, they STINK!!