It’s that thing the space agency has been searching for, especially proof of it on Mars, water. Why? Because it is a building block for life and if you’ve ever ran your air conditioning for an extended spell you might be creating your own petri dish behind your dashboard vents.
You hop in, start the car, and turn on the fan to be blasted with a musty smell. Who turned your car into a sweaty locker room?
There is a unit inside your dash which plummets the air temperature surrounding it, therefore called a heat exchanger. The more familiar term in the auto parts world is A/C evaporator (looks like a mini-radiator). There is a technical reason for this name, but it doesn’t do what you would hope to fix that odor.
If you live in a humid environment and place a nice, iced drink in your cup holder, when you reach for it, you’ll feel the cool slickness of condensation. Fine, okay, simple concept and easily rid of when you quench your thirst and toss the cup in the trash.
Can you imagine what would happen if you left the drink in its pool of water, stagnant for some time in heat and the debris of normal earth’s atmosphere? Things might become a bit boggy, turn slimy like a swamp.
Well, because the heat exchanger in your dash does such an excellent job of cooling the air, it also collects water and if dryer air never gets a chance to brush across this unit, things will get a little musty in your car’s cabin.
Quick fixes for customer complaint in a shop is to spray chemicals on the unit and kill what is living but will not permanently prevent it from happening again. The best option is once you are nearing your destination, turn off the a/c button and keep the blower fan turned on. This will allow your cooling unit to dry off the condensation before it can harbor new life which will provide its proof to you of its existence by a very unwelcoming smell.