I have a 2011 Camry. When you turn on the vent the air smells bad, kind of a musty fowl smell. When the a/c is turned on, no smell. I changed the cabin filter a week ago and no luck.
Mold or other gunk in the evap chamber. Remove the cabin filter. Turn the air conditioner on high speed and shoot a can of Lysol into the intake vents. Be sure to work the head/foot/defrost switch while you’re spraying so that the spray can get throughout the whole system. Then replace the cabin filter.
Hopefully that will take care of it - it should, unless there’s some sort of growth medium in the chamber and insects have laid eggs - if that’s the case it’s gonna require a cleanout.
To prevent in the future, turn the air conditioner off a minute or so before you get to your destination, to let the evap chamber dry out. As the air conditioner runs, the evaporator pulls moisture out of the air - the whole inside of the chamber gets damp. If atmospheric conditions are right and it’s warm out, it won’t dry out on its own, and bad-smelling things love a warm, moist environment to grow in.
I think you have some mold in your vent system. A good detailing shop can get the smell out. That or you can run the vent for a nice long drive on the interstate with the windows down. That will sometimes make the vent air fresher. If it’s still there you can also visit your local detail shop.
my first 75 ford had one problem I could not solve.
apparently someone had puked so violently that it went down the defrost vents in front of steering wheel.
whenever I turned on the defrosters the smell of puke came out as soon as the air got hot. I was never able to fix this in the 6 or so years I had the truck.
at first it smelled like puke every time the truck sat in the sun, but I figured out that the steering wheel wrap was the culprit. every time the sun shined on it , the smell would emanate.
removing the wrap fixed that, but I used ice scrapers and kept a towel to wipe the inside of the window, and avoided the defroster for years