The following is a pictorial guide to changing the cabin filter in a 2013 Ford Police Interceptor Sedan, aka Taurus. From what I have seen, this procedure SHOULD be the same for police and civilian models up to the 2019 model year.
First, get yourself a brand spankin' new filter. We went with a Motorcraft FP-68 (AE9Z-19N619-A).
You will need to remove the glove box for easier access to the old filter. Basically, you squeeze the sides of the box so that it opens all the way... then it falls out and everything falls onto the floor, which is why you will remove everything from the glove box FIRST!
Prior to starting this project, I watched some videos online so I would know exactly where to look for the filter. So when I stuck my head under the dash I started to worry, because I didn't see ANYTHING that looked like the slot where the filter lives. I kept following the vent ducts and didn't see a darn thing... Then I got mad and looked straight forward, and THERE IT WAS.
Basically there is a little cover, or "trap door", if you will, that has two latches and two tabs. Undo the latches, and slide the cover down. Now you will see the nasty old filter staring at you. Slide it out and marvel at the nastiness!
As you can see, the cabin filter DOES actually DO something! This vehicle started life 130,940 miles ago as a police cruiser in New Hampshire, which may explain all of the pine needles and dried leaf bits...
I wrote the mileage and date onto the new filter, just to be anal...
Make sure there's no leftover nastiness in the air-box, and install the new filter.
Now you can reinstall the glove box. This means you can reorganize all of the old registrations, inspection receipts, and sugar packets. NOTE that the left side of the glove box has some sort of plastic limiter which fell apart when I tried to reinstall the box. One end has a tab that slides into a slot on the box. This part connects to a second part with an odd elastic fitting. I think I got everything back together correctly.