Virtually all modern cars, including the Saturn line, have a cabin air filter that filters dust and other particles from the passenger compartment of the car and keeps the interior air fresh. As with all filters, it will need to be replaced when it becomes clogged with debris. Saturn cabin filters need to be changed at intervals of 12,000 to 15,000 miles.
Locate the cabin filter. It is usually found on the front passenger side directly below the glove box or underneath the hood. Another common location is near the cowl or against the firewall on the passenger side.
Remove the cover. You may need to use a flat blade screwdriver to unscrew some holding screws. In that case, turn the screws in a counterclockwise direction and pull them out. In some Saturns, the filter cover is held on by snap clips, which just need to be pulled upward and snapped off.
Pull out and discard the old cabin filter once the cover has been removed.
Slide in a new cabin filter. Make sure it fits beneath the filter cover just like the old one did.
Replace the cover by either tightening down the screws in a clockwise direction or by snapping the clips back in place to hold the cover on securely.
