There are 2 types of filters, just so we are on the same page. One type is the DUST filter, that's located behind the glove box. Then there is the CHARCOAL filter, which is the one I believe you are referring to. It's located under the dash on the passengers side, have to remove a few screws to get the black under-dash panel off, then there are sliding locks that allow the trap doors to be removed to drop out the charcoal filters. i believe there is a website that explains this step-by-step, perhaps you can do a search or someone else may be along presently to give the address for this site.