Why is there no air coming out of the defroster vent?
2 Answers
No air coming out of the defroster vent is caused by issues such as a faulty air conditioning flap, air duct leakage, or a clogged cabin air filter. In such cases, it is necessary to have the vehicle inspected at a repair shop. The automotive air conditioning system, commonly referred to as car AC, is used to regulate and control the temperature, humidity, air cleanliness, and airflow within the vehicle cabin to a comfortable state, providing occupants with a pleasant riding environment and reducing travel fatigue. The car air conditioning system generally includes a cooling device, heating device, and ventilation device. This integrated system makes full use of the limited space inside the vehicle, featuring a simple structure and easy operation, making it a popular modern automotive air conditioning system internationally.
I encountered the same issue last month and was really anxious. If there's no air coming from the defroster vents, it's mostly a setting problem. Check if you accidentally pressed the mode switch button - some cars automatically switch to footwell mode. Additionally, a dirty cabin air filter can block the airflow, especially in northern areas with heavy sandstorms. If left unchanged for two years, it can get completely clogged. A faulty blower motor is also a common cause - you can usually hear a humming sound but no air comes out. If all dashboard displays are normal, then you need to check the air blend door actuator. If this small valve gets stuck, it can cause airflow distribution failure. I solved it later by cleaning the filter myself, saving 500 yuan in repair costs.
