Here is a DIY to replace or check your cabin filters. These are the filters for your cabin ventilation, not your air intake filter in the engine bay!
You'll need:
1.) Trox bit set
2.) Replacement filters(if needed)
3.) Low profile(short) screw driver
It took me about 30 minutes total, taking the under dash panels took a bit longer as it was my first time doing it, but reinstalling was a breeze. Here goes!
You're going to look under the dash/footwell area of the passenger side. Pretty cool because I actually never new there was another a/c power plug there. Nice!
You'll see a total of 4 screws holding the entire panel, point upwards. There are 2 bigger ones, and 2 smaller ones. Undo those 4, and there is one more screw which is the one on the side of the footwell area, and it screws in towards the driver side.
With a little work and being careful with the panels, you should be able to slide that whole underpanel out safely, but watch out for the 2 wires that are still attached. One of the is the power wire for the A/C port, and one is for the airbag. You A/C power wire slides off easily, but the airbag wire I left connected. It has enough slack for you to rest the entire panel on the floor of the passenger side, and access the cabin filter compartment.
Now, you will see a grey hose going into the cabin filter compartment, simply slide it off.
Holding the lid for the cabin filter compartment is 4 silver screws pointing/screwing upwards. Undo those 4, and you are basically good to go. Here are some shots of the 4 screws and a picture of the compartment cover off:
[URL=http://imageshack.us/photo/my-images/525/32622006.png/]
At this point you can check or replace your 2 cabin filters, and put the dash panels back together!
***NOTE: When you reinstall the bottom panel as one whole assembly, make sure that the 2 plastic tabs on the back of the panel line up with the slots under the footwell area, or else the panel wont go back in place properly!