Where is the cabin air filter located?
Cabin air filter on 2004 Ford Taurus
Here are some instructions on how to replace your cabin filter: http://www.filters-now.com/pdfs/micronAir/fd96102p.pdf
The cabin air filter is at the rear of the engine compartment passenger side at the bottom of the windscreen. There are some clips and a water shield to remove to gain access to the filter.