How to distinguish between internal and external circulation with one button?
2 Answers
Method to distinguish between internal and external circulation with one button: Press the air circulation button, the light on indicates internal circulation, and the light off indicates external circulation, meaning turning off internal circulation switches to external circulation. Car air conditioning generally includes cooling devices, heating devices, and ventilation devices, with modes divided into internal circulation and external circulation. Internal circulation is typically used during traffic jams. When turning on the cooling air conditioning, first activate internal circulation to lower the temperature inside the car, then switch to external circulation after some time. Internal circulation means air circulates only inside the car, driven by the blower to cycle the interior air. External circulation connects the interior with the outside; while driving, airflow automatically draws in outside air due to wind pressure, and when stationary, outside air can still enter the blower through the air ducts and be blown into the car.
Over the past decade of driving, I've become quite familiar with the air conditioning buttons. Typically, there's a button with an icon showing a small arrow circulating inside a car. When the light is on, it indicates the recirculation mode is activated, meaning the air only circulates within the car, like being trapped in a box. This is especially useful in urban traffic jams, as it blocks exhaust fumes and dust, and the AC cools down faster. When the light is off, it's the fresh air mode, drawing in outside air—similar to opening a window for ventilation but without wasting cool air. Once, I drove a long distance with recirculation on the entire way and ended up feeling dizzy. Since then, I've learned to switch modes appropriately: use recirculation in areas with polluted air and switch to fresh air mode on highways for a refreshing breeze. Also, don't forget this button is simple to operate—just press it, and the light change is obvious. Don't be lazy; always check the indicator light.
