FYI Class Action HVAC Stinky

[jrandom]

Toyota states the procedure in the 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.
• The start timing of the blower may be delayed for a short period of time immediately after the air conditioning system is started in automatic mode.

because that's dumping humid unconditioned air back into the vehicle, the proper solution is designing a housing that will drain and not hold water

You’re not wrong. A plugged drain was the issue I had. The end of the drain tube attracts grime, it could be as stupid as the radiator fan consistently blowing material in its direction, don’t know but the fix take literally a few seconds.