Hi,
Unfortunately, there are no cabin filters in our Pumas but that doesn't stop you from doing some DIY simple filtering to keep the bigger stuff out of the system.
As for the smell, I've only had the system smell bad on one occasion and that was when my ignition switch was melting and fusing one of the plugs to the pins. Smelled of something decaying together with a pee like smell. Once the offending switch was found and replaced, lo and behold, no more smell.
Have you had your system cleaned? Maybe it's time to give the 'ol cooling coil a good wash then top off your refrigerant and compressor oil while you're at it. I make it a point to have it cleaned and checked once a year just to be safe.
I hope this helps.
