Drew R. Ask’s : My Heater and A/C systems blower fan performance is poor why?

Well Drew Here is what might be going on with your  heating/ air conditioning  system in your car. Around 1998 or so some automotive manufacturers started to add cabin filters or also known as pollen filters to the heating and air conditioning systems of their vehicles. Today almost all vehicles come equipped with these filters installed in the heater blower housings. The problem is that most people do not know that their car even has one! I have had customers come in to the shop I work at for a service and removed the cabin air filter to inspect it and it was beyond dirty. If you look on page 129 of my

book “If That Car Could Talk “You will clearly see exactly what I am talking about. This filter was the dirtiest cabin filter I had ever seen even dirtier than the one pictured above on the right, and I am not sure how air even passed through it!

The tell tale symptoms you should look out for that may indicate that your vehicles cabin air filter may need to be replaced are as follows.

  • Decreased air volume flow from your heater vents.
  • Musty or foul odor from your heater or defrost vents.
  • Poor defroster performance.
  • If you have allergies you may notice them flaring up when you drive your car.


Most new model vehicles have cabin filters that are fairly easy to replace and if you are a do it yourselfer may want to try and tackle it yourself. Most cabin filters are located behind the glove box area. Some vehicles have cabin filters that are hard to locate and even more difficult to replace. Make sure you know what you are getting into if you are going to try to attempt to replace your cabin filter.

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