How To Diagnose A Failing Cabin Air Filter

When your cabin air filter gets too clogged up, your car's HVAC system is compromised. More specifically, the HVAC system has to work harder to push the air through the filter, which can burn up the blower fan motor. A clogged air filter can also cause respiratory issues and foul odors inside the cabin.

That's why it's recommended to replace your cabin air filter every 15,000-20,000 miles. Sometimes a cabin filter would need to be replaced sooner, especially if it's continually exposed to heavy dirt, dust, and/or pollution. It's a good idea to check your air filter once a year or whenever you notice some symptoms.

This diagnostic guide will walk you through the process. Luckily, it's a pretty easy and straightforward process. All you have to do is to pull out the cabin air filter and then visually examine it.

Telltale Signs of a Clogged Cabin Air Filter

If you're looking for good indicators of a clogged cabin air filter, look no further than this list:

  • Weak airflow through the HVAC system
  • Stale and foul odors from the vents
  • Increase in allergy symptoms and respiratory reactions

Finding the Cabin Air Filter in Your Car

GM filter location

Image Credit: PaulsTravelPictures

The location of the cabin air filter varies between GM models. Each model also has its unique way of accessing the cabin air filter. Check your owner's manual for the location of the cabin air filter and how to access it.

For example, the cabin air filter in a 2014-2018 GMC Sierra is located behind the glove box. Here's how you can access it:

  1. Open the glove box.
  2. There are four T15 screws: one on each side of the panel inside the glove box, and two underneath the glove box door. Remove them all. Use a magnet to prevent any of these screws from falling into another panel.
  3. Gently remove the glove box door and the panel attached to it. You may have to wiggle it loose.
  4. Now you can see the cabin air filter cover. There are two tabs on the top edge. Lift them up and then remove the cover.
  5. Pull out the cabin air filter.

Inspecting the Cabin Air Filter

Cabin filter GM

When you have the cabin air filter in your hands, it's time to visually inspect it. It's quite easy to do. First, you want to find a bright light like the sun. Hold the air filter in front of the bright light. Can you see some light shining through? If your answer is yes, then the air filter still has some life left. If you can't see any light shining through, then the air filter is no longer good.

What if You Need to Replace the Cabin Air Filter?

Replacing the cabin air filter is even easier than checking the old cabin air filter. All you have to do is to access the cabin air filter, pull it out, and then put in the new cabin air filter. We offer affordable prices for genuine OEM GMC cabin air filters here. Just look up your model to find the right air filter for your car.