I noticed that the filters were just as dirty on one side as they were on the other side. It seems to me that a filter should have more dirt on the intake side indicating that it is not letting some of the dirt go through the filter and into the cabin.

I would have thought the same. I guess now I have to check out my filters!

Are the filters the type that debris enters from the outside but filtered air flows from the inside? You could also have a bad seal on the edges of the filter cartridge/element.

Regards,

Are you sure that they were not reversed by someone, instead of being replaced? It makes no sense to me...air flows only one way through the cabin filters, Tim