How do leaves get into 2005 tundra air vent systems fan?

Hello, The air comes into the HVAC system through the cowl, right underneath the windshield wipers. It is very common to find leaves inside the HVAC assembly, but cleaning the fan area out five times on a 12 year old vehicle is excessive unless you always park underneath trees. There is no cabin air filter, so there is no barrier between the fan and and debris that makes it through the vents on the cowl. Also, yes, animals can go in there if the cowl is damaged, but they would have to be VERY small.

Yes - small rodents surely can get into the HVAC system! .. Remove the *cabin air filter* and you will likely find the problem....... The link below should help: https://www.youtube.com/watch?v=nOkROZu4l78