What is it?
They filter the air that comes out of the heater and AC vents. When clogged/dirty the blower motor works harder to move the air through the vents, therefore the AC cannot blow as cold.
Where is it?
They are located in the ductwork that delivers outside air to the HVAC (Heating, ventilation, and air conditioning) system. In most cars, you can find them under the dash or behind the glove box.
What to do now?
Most cars need one annually. If you park your car under trees or you drive in a dusty environment, then you would need to change your filter more often.
