What Causes No Airflow from the Front Windshield Vents?
2 Answers
The lack of airflow from the front windshield vents is caused by a malfunction in the vehicle's blower motor. It is necessary to promptly visit an auto repair shop to service or replace the blower motor to resolve the issue. Details about car air conditioning faults are as follows: 1. Air conditioning fan control circuit: The system controls eight serially connected air flap motors in the HVAC system via a LIN bus. Each motor contains a measurement resistor of approximately 1Ω, connecting downstream motors to upstream ones through this resistor. 2. Potential fault points: Possible failure locations include: the air conditioning control unit, fan output stage, signal wiring between the control unit and output stage, fan motor, control wiring from output stage to motor, as well as power supply and grounding circuits of the fan output stage.
A few days ago, my car had the same issue, and I found that the most common cause is actually incorrect air conditioning mode settings. To direct air to the front windshield, you need to select the vent position with the windshield snowflake symbol—many people forget this. Then, check if the fan speed knob is turned too low or accidentally turned off. A dirty air filter can also block airflow; I replace mine every six months. Another hidden issue could be a faulty blend door actuator, which is the small motor that controls airflow direction. Lastly, check the fuse—the dedicated fuse for the front windshield heater is in the box under the steering wheel, and replacing it yourself costs just a few dollars. If you’ve checked everything step by step and still no airflow, then it’s time to visit a professional shop to read the fault codes with a diagnostic tool.
