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Not Enough Air Flowing Through The Vents Inside Your Car? Here's What Could Be Causing It

If your car's air conditioner is running but you're not receiving much airflow into the interior, driving quickly becomes uncomfortable. If none of the air is blowing on you and your passengers, it doesn't matter how well the air conditioner itself is working. Thankfully, diagnosing this mechanical problem is often simple. If you have low airflow inside your car's cabin, read on to find out what could be causing it.

1. Clogged Cabin Air Filter

The easiest problem to fix is a clogged cabin air filter. Depending on your make and model of vehicle, it will either be located behind the glove compartment or underneath the driver's side dashboard. If you haven't replaced your cabin air filter for years, it may have become clogged with dust and pollen — this will significantly reduce airflow through your vents. If your cabin air filter is clogged, you can either clean it or replace it in order to fix your car's air conditioner.

2. Obstructed Blower Fan

Your car has a blower fan in the engine compartment that circulates air around the interior. When you're not getting much air from your car's vents, it may mean that the blower fan is obstructed with debris.

There are several ways that debris can become stuck in the blower fan. Squirrels, mice and rats sometimes make nests in the engine compartment, and nesting materials can fall into the blower fan assembly. Road debris like gravel can also sometimes obstruct the blower fan if they pass through your car's air intake. Inspect the blower fan for any obstructions and remove them, which will allow your fan to spin at full speed again.

3. Failed Blower Fan Resistor

The speed at which your blower fan spins is determined by how much power it's receiving. The blower fan motor is connected to a resistor that limits the flow of electricity, and you adjust this resistor with the fan speed setting on your car's central console.

The electrical current running through the resistor causes it to heat up, and excess heat can cause the resistor to fail. Once it fails, your blower fan will be stuck at a single speed setting — in this case, it's stuck at a low speed. Removing your blower fan and replacing the resistor will allow it to receive full power again.

4. Stuck Blend Door

If air is coming from the vents underneath your windshield but not from the vents in the interior, your car's blend door may be stuck. The blend door determines the direction of air flowing through your car's air conditioning system — it directs air towards the windshield vents when you have the car's air conditioning system in defrost mode, but otherwise directs air into the car's cabin.

Blend doors are controlled by an actuator, and the motor inside the actuator assembly can fail. Without the motor, the blend door can no longer move in order to adjust airflow throughout your car. Essentially, your car may be stuck in defrost mode with little air blowing into the cabin. Replacing the broken actuator allows the blend door to move again, allowing you to switch off defrost mode.

While replacing your cabin air filter is easy, replacing a blower fan resistor or blend door actuator can be quite challenging depending on your make and model of car. You may have to remove several engine components to access the blower fan, and you may have to remove the dashboard to access the broken blender door actuator. If repairs are outside of your mechanical comfort zone, take your car to a local auto A/C repair shop to have your car's air conditioning system inspected and your low airflow problem resolved.

If you want more information, visit a service such as Fantastik Auto Repair.