Does your vehicle air conditioner smell sort of like mold, especially right when you first turn it on? If so, you’re not alone – it’s a very common problem. Here in Phoenix, this can be an especially annoying problem because so many of us use the air conditioner every day.

The cause of this problem is just what it smells like – mold and bacteria. Inside your vehicle’s air conditioning system, you have a part called an evaporator. This part is designed to remove both the heat from your vehicle’s interior (when the A/C is turned on, anyways) as well as remove any moisture from the air that’s being cooled. While most of the air around here is pretty dry, there’s still enough moisture in the air to condense upon your vehicle’s evaporator.

Vehicle air conditioner evaporator

An evaporator from a vehicle air conditioner, removed from it's housing

When moisture condenses on the evaporator, it’s supposed to drip drain away. However, very often the drain will become clogged and/or it won’t drain quickly enough. If water can stagnate inside the evaporator unit, this water grows mold and bacteria that causes your vehicle’s air conditioning system to smell — especially immediately after the system is first turned on.

There are three ways to solve this problem:

read more