Was taking out my cabin filter and there is a bunch of loose insulation wadded up behind the filter. Is it supposed to be there? Or is it a mouse house?
That is rodent mouse bringing in stuff to make a nest with they didn't put a hole in the filter and go through it so they must have just been hanging out on top of it so you have mouse and rodent problems wherever your parking your car You want to suck that mess out of there with your computer vacuum tools that you use on a Shop-Vac that are sold by the shop vac company or whatever you can get in there to suck all that mess out I bet if you took your fan out Mr right above your feet when you're the passenger You would find a bunch of mouse feces laying on the fan plate might want to clean that out I don't know personally. You want to figure out why you're getting these roads I guess it's because where you live and maybe figure out what those rodents don't like some kind of noise heavy metal music I don't know but something and work that out because they will eat the soy-based wiring and all kinds of stuff and it's a lot of fun not.
Mouse. Take off the wipers and cowl, mesh the cabin air intake with 1/4" galvanized steel rodent mesh. Self-tapping sheet metal screws work good for fastening it. Doesn't hurt to mesh the open end of the engine air intake snorkel too. There's also two flaps at the back corners of the car, just below the hatch floor. They're awkward to mesh; still something else to consider. I haven't done those yet.
Welcome to the forum. Mice and the Prius can be a huge, very costly problem, if you don't nip it in the bud. Toyota uses a wire covering that is different than many OEM but is better for the environment. It has proven extremely tasty to mice. If you mice tenants start eating the wiring harness, you could be looking at thousands in repair costs. Mendel Leisk is our resident mouse expert. Check out his posts in this thread: MouseProofing the Prius ========= Whoops -- he was typing while I was typing!!
Post #183 in the above link posted (in post #4) shows the cabin air inlet mesh nicely. See also #198, for meshing of the rear air exit flaps, below hatch floor. I really should get on that; haven't done it yet. The vents look a little different (from a Prius v). Not also, the 12 volt battery probably needs to come out, for access.