Moldy smell when fans turn on

Yes, it's a known issue in Toyota's for years now.

Master Toyota mechanic "The Car Care Nut" has a video on how to disinfect the A/C system. But, in the meantime, he suggests you turn the A/C compressor OFF when the car is done being used for the day and blowing the fan on HIGH for at least 5 minutes as you are parking it. This dries out the wet insides of the A/C system which can help prevent the nasty smells.

Also check your cabin air filter, make sure you have a carbon activated one. If it's not, replace with one. (I don't spend the crazy expensive cost of a Toyota OEM filter, I like the Fun Driving charcoal filters they sell on Amazon...for our 2017/2021 Prius, it's $22.48 for 3 of them.

 

Just typed in another thread:

Cabin / Air Filter Combo | Page 2 | PriusChat

 

I saw that, Mendel...thanks! Seems to be a common complaint with Yota's around this time of year!!!

Have you ever done one of those Toyota A/C disinfectant jobs? I never have but if they aren't too hard I might be inclined to clean our 3 Yota's before winter comes.

 

A filter replacement isn't going to take care of this issue. You have mold spores all around you. All they need is a cool, damp, dark environment to grow in. Your AC evaporator is the perfect spot for them.
1. Check your filter & evaporator drain. Make sure they're not clogged
2. Place the climate system in manual mode. Temp. 68-72 degrees, fan on low
Whenever you use the AC, turn off the compressor 5-10 minutes before you reach your destination. That will dry out the evaporator area and prevent mold from forming.

Hope this helps...

FYI: That's how I've got my car setup, never any mold smell...

 

try turning off the a/c a mile or so before your destination

 

You need this injected into your condensate line with the cabin filter removed. Works.