Cabin Air Filter

Most cars manufactured since around 2000 have an air filter for the HVAC system, the cabin air filter. It is pretty standard to locate these on the right side of the car inside the dash, accessible by removing the glove box or lowering it beyond its normal travel. I work mostly on Toyota and Honda small passenger vehicles and I believe they all follow this pattern. A few exceptions that I can think of are the Ford Escape, VW Jetta and Think, all of which have cabin filters accessed from under the hood (still on the right side of the car).

It’s usually a quick and easy check to do, so I always include it unless the customer is in a real hurry. But it seems that the word has not gotten out to all of the service shops and technicians. For some cars visiting Hawthorne Auto Clinic for the first time I may find a relatively new, clean air filter. But the other times…

I don’t know what it is about Prii particularly, but the engine compartment and cabin air filter are places that rodents love to hang out.

Today I encountered a situation I have never seen before: The cabin filter was literally packed over-full with sunflower seeds. Even as I started to pull the filter out to check it I heard seeds being pushed off the back side, falling down into the blower.


Thankfully the customer agreed not only to replace the filter, but also to pay for a little more time so I could disassemble the blower box and get all the seeds out.
This was the first time that I had removed a Prius blower and it turned out to be easier than I had anticipated, which is almost never the case. There is a cover under the passenger side dash that is held in place with 2 clips on the aft side. The transmission control module is mounted to the the underside of the blower box with two screws. The bottom cover of the blower box is held in place with 5 Phillips head screws, and the blower motor assembly comes out with 3 Torx 25 screws.

When I pulled the filter our fully I saw what I presumed to be the source of all the sunflower seeds: A tiny, dessicated rodent, perhaps a victim of karoshi, death from overwork.




The previous images were novel to me, but the ones similar to the following are unfortunately all too common:









But cabin air filters aren’t the only place rodents will take up residence inside the cabin (and they are much more frequently visitors to the engine compartment). Under the spare tire seems like a safe, secure place to make a home:



By the way, in case any Think owners mistakenly have read this and thought that they have been breathing deceased-rodent air, there is no need to worry.  So far every Think cabin air filter I’ve inspected has been slightly dusty at worst.

One thought on “Cabin Air Filter”

  1. Yes, the animals of the wilderness.

    Sometimes in Sweden, the mice nibbled my chainsaw useless and even a hole in the chain oil reservoir. Damned!

    So be really angry, I can not give them.

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