Where is the cabin filter located in a 2004 lincoln towncar

SOURCE: Location of the fuel filter in a 1999 Lincoln Towncar

It is either along the frame rail, probably drivers side under car follow the metal fuel line or it is in the gas tank right at the fuel pump, either requires removing tank or carpet inside trunk to get to access panel, but your problem is probably not fuel filter, with todays clean fuels fuel filters are a problem of the past, used to be a easy fix but that is why they hide them now because they are usually good for life of vehicle, 1999 is not old enough to make difference in this situtation.

SOURCE: lincoln continental cabin filter

I solved the problem by ordering the filter fro an online site that gave instructions:

http://www.cabinairfilters.net/cabin%20air%208467.htm
instructions at this link are:
Turn on wipers until they are in an upright position then turn ignition off. Open the hood. The filter compartment is on the passenger side, directly beneath the windshield. Pull back weather strip and remove cowl. Slide the water shield toward the front of the vehicle then lift to remove. Replace filter and reassemble.

I have it out and am waiting for new filter.

SOURCE: where isthe cabin air filter

Passenger side,open hood,remove most of the push pins, holding wiper cowl grill to cross brace.
Under the plastic cover is a box with another cover, and inside the cabin filter.
They are expensive and last about 3 years
Get real dirty after two

You will break a few push pins and the dealers don't stock and they are too expensive,like $3.20 ea
Use wire ties until I find a source at auto body supply houses