If a customer complains of low airflow from the dash vent, what could be the cause?

A restricted cabin filter can significantly reduce airflow to the dash vents, causing the customer to perceive low airflow. The cabin air filter's purpose is to trap dust, pollen, and other airborne particles before they enter the vehicle's interior. Over time, this filter can become clogged, especially in environments with high pollution or during the pollen season. When airflow is obstructed, the air that gets through will be weaker, resulting in insufficient cabin ventilation.

While a malfunctioning blower motor could also affect airflow, it typically wouldn't solely be due to a lack of effectiveness from the motor itself, but rather issues related to power supply or operation. Low engine coolant levels primarily impact the heating system rather than the ventilation directly, as they affect the heat exchanger's ability to transfer heat, possibly leading to no heat rather than low airflow. A leak in the ductwork can also cause airflow issues, but it tends to involve a situation where air is lost before reaching the vent rather than a consistent low airflow problem from the vents themselves. Therefore, a restricted cabin filter is the most direct and common cause of low airflow complaints from dash vents.