One day the car began to smell awful. Thought it might be some food left under the seats by our kids, but nope - cleaned the car, smell got worse. Realized, with a sinking feeling, that it smelled worse whenever I started driving or turned on the blower fan.

Started searching with the cabin air filter. Found a large mouse nest right on top with 5 not-so-freshly-dead mice. YUCK.

The cabin air filter is easy to get to, right behind the glovebox. Open the glovebox, press in the sides & two plastic nubs will get past the side trim. Then pinch the end of the plastic shaft on the right-hand side & the piston will pop off. Then pull the entire glovebox toward the seat to pop it off the hinge.

Flip up the panel behind the glovebox & you'll see the cabin air filter, & in my case, the nest on top. Be careful if you're in the same situation to get as much of the nest out before moving the air filter, because otherwise all the nest & other crap (literally) will drop down into the fan.

Pretty stupid design shortcoming to make the vent system accessible to mice. I wish Toyota had designed the vent system with a few plastic bars on the intakes so mice couldn't get in. The cabin air filter sounds like a great idea until it starts blowing mouse dropping dust & urine residue back into your face.