Originally Posted by Anvil
Can you please be more specific???
My hunch is that most of the molds would grow at or near the evaporator where the cold moister condenses and remains on the cold surfaces when operation ceases.
Can you actually easily get to those locations?
Well I'll upload a couple pics. What you see in the first picture is the engine bay. I circled the HVAC ducting. You pull off the cowls on the left and right, then unscrew the ducting (six 8 mm screws) and then pull off the bigger cowl underneath the ducting (2 more 8 mm screws and some rubber tabs) after just unclipping the two rubber hoses running in front of it.
You should then be left with the underside exposed, like in this second picture, which shows where an OCC would install under all that:
In the second picture I circled one of the two rectangular holes (the only one visible since it's a zoomed in pic towards the driver side of the engine bay) where the HVAC ducting screws into. The ducting you took off will have the filter in it, with lots of little crevasses where fungus and bacteria love to grow. The evaporator/refridgeration unit is built a little further into the car, so you can't physically take it out or anything, but if you look at the way the ducting goes, spraying into the rectangular holes is MUCH more direct than sucking in the a spray cleaner from the exterior of the car.