Conditions when car trouble occurs
When the car air conditioning is turned on, the air that comes out the air con vents is with mildew odor.
Possible cause of car trouble
Drain pan of AC unit is not draining
Car problem troubleshooting
Car air conditioning has a component called the evaporator, when the air conditioning is turned on the evaporator gets very cold then if the air is blown through the evaporator the air will turn out to be cold after it passes the many fins of the evaporator and going out the air conditioning vents. Now, during hot and humid days a condensation is formed on the evaporator because the evaporator is cold. The moisture that is formed will drip down into the drain pan of the evaporator unit and then it is funneled down a hose going out the road.
When there is clogged somewhere in the system the drain pan will not draining and the moisture will get trapped in the drain pan. The trapped moisture will encourage the growth of algae-like organism that will create a mildew odor which can be transmitted all the way up to the evaporator.
If the mildew odor reaches the evaporator the smell will then be carried by air going out the air conditioning vents.
How to fix the mildew odor coming out the car air conditioning vents
First thing to do is to locate the hose that is connected all the way to the evaporator drain pan. If you cannot locate the hose you may refer to the manual that covers this car for reference on the location. If you located the hose, check the end of the hose if there is debris or mud and clean if necessary. If the end of the hose is no clogged then check the base of the drain pan it might be in this portion where the clogged is presence again clean the hose if necessary. Once the clogged on the system is cleaned the drain pan will drain properly. But the mildew odor will not yet be removed it will take a couple of days the mildew odor will completely remove.