Gen 3 Prius Air Recirculate Problem & Fix

So I recently noticed that when I had the air recirculate option selected on my car that air was still coming through the vents while the car was in motion and I could smell heavy exhaust from the cars in front of me. Switching it back and forth seemed to make no change. After researching other threads, some simply said that this was normal which I knew was incorrect because it's never done this before.

After some digging, I noticed that the previous owner installed the cabin air filter incorrectly causing it to compress. This in-turn caused the pin to detach from the device that opens and closes the vent. I did not know where the vent was at the time but after pressing the button over and over again, I was able to figure it out. Oddly enough, the device would open the vent but not close it.

I re-attached the pin to what appeared to be the correct position but the vent still would not operate correctly. I detached and tried a different position and boom, we were good to go. My point in stating this is that the position of the pin does matter. When you press the air recirculate button, you should see it move between both positions.

I took the car for a test drive and all worked as it should. I've attached photos which details the above. You should research how to access the cabin air filter of your car before attempting this fix. A small and fairly long screwdriver made this process much easier as I had to pry them apart from each other to get them in the correct position. If anyone has questions regarding the above, let me know in the comments and I'll do my best to clarify.