If you live in an area where field mice live, you might find mice getting into your car as I have. I found that in my 1999's body style, there are provisions for a cabin air filter (in the windshield wiper trough), but none was ever installed from the factory, and the auto parts stores claim there's no part number for one. This area leads directly into the car under the dashboard. Since there was evidence of a mouse right at that spot, I looked to block the hole, and found that the 2004 Grand Prixs came with that filter. I bought one for a 2004, and it fit perfectly, blocking the gaping hole into the car.
Years later, I got another mouse in the car and coincidentally found the paper filter had a hole chewed in it. This time, I bought a K & N (washable) cabin filter that has a metal screen on both sides. Hopefully, this will deter them.
So if you are getting mice in your car, and are confident you have no rust holes underneath, you may want to consider this.
