I replaced my cabin air filter as part of my 90k mile service. The cabin filter is not part of the standard 90k service, but I had a feeling (which seems to be proved) that my filter was original to the car. Now was a good time to correct that issue.
I won't go into great detail about the removal process because there are several good sites that explain in detail how to replace the cabin filter in the SAAB 9-5.
Old filter, possible from 2000 with 90k miles on it.
Brand new filter from TheSAABSite
I was shocked how large the filter is, it's about has the width and length of a sheet of paper. I always imagined it to be maybe 4x6 inches. I thought they had sent me the wrong filter when I opened the package and saw how big it was.
You start by removing the carpeted cover on the passenger's side foot-well, there are a few plastic rivets holding it on.
Then the plastic dash panel and glove box are removed, around 6 or 7 Torx screws are holding them in place. The glove box has an air duct and two wires that will need to be pulled off before the entire box can be removed.
There are about eight Philip head screws holding on the black plastic panel that seals the cabin filter. The panel is in the lower right side of this image
Once the panel is gone, remove the old filter by moving the cable bundles to the side and sliding the filter out. You might want to put something down because my filter was host to a handful of tiny leaves and damp rotten foam chunks.
The new filter is installed in reverse, the supplied foam goes in first, at the top with the holes fitting over the two pipes. The new filter can then be slid in with some delicate pressure. The black plastic panel is reinstalled, the wiring and ductwork for the glove compartment is reattached and the box is installed, the dash panel is returned into place and the carpeted cover is riveting back. That is all there is to this project. It was easy to do and only took about twenty minutes to complete.