Do You Need to Turn on AC for Defogging?

[EmiliaAnn]

You need to turn on the AC. As long as the defogging switch is turned on, or the air direction is set to the windshield mode, the AC switch will automatically turn on, and the circulation state will switch to external circulation. Turning on the AC and external circulation can achieve the fastest and best defogging effect. Some cars allow manual AC shutdown, while others do not. If the AC is turned off in defogging mode, defogging can still occur, but sometimes the effect may be worse, and the fog may take a long time to dissipate. Here are the specific details about the AC button: 1. Meaning: "AC" is the abbreviation for "Air-conditioning." Pressing the "AC" button activates the air conditioning to adjust the temperature according to the set value. If turned off, only the blower operates, and the temperature adjustment mechanism does not work. 2. Function Introduction: The automotive air conditioning system, commonly referred to as car AC, is used to regulate and control the temperature, humidity, air cleanliness, and airflow inside the vehicle cabin to the optimal state. It provides a comfortable environment for passengers, reducing travel fatigue, and creates favorable working conditions for the driver, playing a crucial role in ensuring safe driving. Generally, it includes a cooling system, heating system, and ventilation system. This integrated system makes full use of the limited space inside the car, features a simple structure, and is easy to operate, making it a popular modern automotive air conditioning system internationally.

[VonLeilani]

I've been driving for ten years and have encountered fogging countless times, especially on humid rainy days or cold winter mornings. That time on the highway when mist covered the windshield, making it hard to see oncoming traffic, I immediately turned on the defogging mode—the AC automatically activated with high fan speed. The AC's role is dehumidification, just like a home air conditioner, condensing and removing moisture from the air to prevent water droplets from forming on the glass, clearing the fog much faster. Without the AC, relying solely on heated air can slowly evaporate the fog, but in very humid conditions, it may take too long or even fail, compromising driving safety. Now, I make it a habit to set the temperature and fan as soon as I start the car, keeping the windows clean to avoid distractions.