moldy smell

OK, here is my simple fix- I always turn off the a/c while driving the last few blocks home and run the fan the rest of the way. I then leave at least one window open. (I park in my garage.) I also leave the windows cracked just a bit when parking outside. This has worked on three Prius for me, along with several other makes.
I'm guessing that the dealership fix is to spray a mildew killer like Lysol into the fresh air vents outside the car with the fan running. That you can do yourself, but if the car is given a chance to dry out it should take care of the problem. Your summer humidity contributes, but I have also noticed if water collects on the all weather floor mats from washing or rain, a mildew odor develops. The first time I ever had the mildew problem was in the summer in Kentucky. I took the car to a dealer for service and ask them to check the underside for roadkill, the smell was so bad.

 

That "shut off a few blocks before you arrive" advice is priceless.

How else is the system going to purge the moisture inside if you abruptly make it stop immediately upon reaching the destination? It needs to circulate without the condenser for a little bit.

With the plug-in model, there's the benefit of saving a little tiny bit of electricity from doing that too. Then there's the added bonus of not blasting people with nasty air later when you start up again. Sometimes, like in the evening, you don't need to A/C anyway. So having it off already can be a bonus.

 

From the Toyota manual
■Air conditioning odors
●During use, various odors from inside and outside the vehicle may enter
into and accumulate in the air conditioning system. This may then cause
odor to be emitted from the vents.
●To reduce potential odors from occurring:
• It is recommended that the air conditioning system be set to outside air
mode prior to turning the vehicle off.

 

Excellent

 

Wonder if the solar roof changes the picture since it circulates air from the outside if the temp is above 70 degrees

 

I don't think anyone yet mentioned the A/C filter in glove compartment needs replaced could be the whole problem, assuming Gen3 also has this same filter?

 

You can also get the filter off Amazon for a few bucks...they recommend 6-months...the cheap filter on Amazon is OK (I just got one) but there are some activated carbon ones for more money. Good luck with the car!

 

I have noticed that it seems to automatically switch to inside/recirculate when I use the a/c on hot days, and back to outside air when I switch the a/c off but leave the fan going. BTW, I never use the "AUTO" function.
I used to work at a Mercedes store, and we had many customers come in with a similar complaint during the warmer months. It was a quick fix in the service drive to spray in something like Lysol. If that didn't cure it, an expensive shop visit might be required. In my earlier post, the car in question was a Cadillac, and the dealer checked to make sure the drain line from the system was clear. I have heard of the complaint on different makes of cars, so I don't think Toyota is alone on this one. Maybe this was a "perfect storm" combining humidity, temperature (system staying in "recirculate mode") and a tight car body? I've noticed it in my Lexus all three Prius I've owned if I don't follow my habit of switching off the air prior to parking for the night.

 

Ozone

 

Yep, I've used that one also.

 

I've noticed that mold smell the last few days too... we just got over a 10 day heat wave with temps in the mid 90's to 100 so the AC was on constantly.

You say you sprayed with the tube in the "center dash air vent"? Is that the two vents directly over the CD player slot?