Windows up, circulation vent closed, didn't eat through the ac/heat ducting ( like the one that totaled my 2007). I'm stumped. Where is the hole?
I got nibble damage to the cabin air filter once. (I always buy the one with carbon added which is toxic to eat). Never happened again but I do check/change it every 1 1/2 years.
They enter through the fresh air vent up front. There are diy screening options. Fyi, fresh air is partially open even in recirc mode. Mice can chew through lumber if the want to, so going through a flimsy plastic damper is child’s play. In the end it is better to get rid of the rodents, generally with rat poison around the property.