Which Button is for Defogging?

[LuciaDella]

There are two defogging buttons in a car. One is for the front windshield defogging, marked with a fan-shaped symbol containing three upward wavy lines. The other is for the rear windshield defogging, marked with a rectangular symbol containing three upward wavy lines. Here are the related details: 1. Defogging: The principle of fog formation on car windows is due to the temperature difference between the 'cold outside and warm inside.' The temperature inside the car is higher than outside, leading to fog formation. Turning on the A/C switch activates the cooling state, which has the advantage of quickly removing fog but is not suitable for winter. Another method is using the heating system for defogging. This method is also effective, but it takes a few minutes to work. 2. Benefits: The car defogging button can reduce moisture, fog, and frost on the front and rear windshields and the exterior rearview mirrors, improving the driver's visibility and making driving safer.

[Valarie]

I have so much experience with this issue, having driven for over a decade and using it every humid season. The front windshield defogger button is that fan-shaped icon with wavy arrows, usually located above the center console’s AC panel. The rear windshield defogger is a rectangular icon, often shared with the rearview mirror heating function. On rainy foggy days, I just press the fan-shaped button, and the AC automatically switches to external circulation with high airflow directed at the glass. But be careful not to turn on the heater immediately after starting the car—the temperature difference can actually worsen fogging. Wait for the engine coolant to warm up first for optimal defogging. Ventilating the car by opening windows before parking helps reduce fogging, and regularly cleaning the interior side of the windshield is also crucial. If you neglect these details, even pressing the right button won’t give you the best results.

[Barry]

I often encounter this situation while driving. Last time during heavy rain, the windshield was completely fogged up and I couldn't see the road clearly. The defogging button is easy to recognize - the front windshield defroster has a fan-shaped symbol with three small arrows, located in the most prominent position of the air conditioning control area. After pressing it, you'll hear the fan suddenly increase speed, blowing directly onto the glass for dozens of seconds until the fog clears. It's recommended to turn on the AC cooling for a few seconds before using warm air for defogging in winter, as this quickly removes moisture before switching to heating to avoid secondary fogging. If the rearview mirror frosts over, you can simultaneously press the rear defogger button, and the heating wires will also warm the mirrors. Avoid placing too many moisture-heavy items in the car, and closing the sunroof while using the AC works better.

[ElisaFitz]

As professionals frequently handling car air conditioning repairs, we encounter defroster button issues daily in our workshop. The front windshield defroster button icon resembles a fan shape with an arrow, while the rear defroster has a rectangular icon. The key lies in using it wisely: don't immediately turn on the heater for defogging when starting the car - the clash of cold and heat will only worsen the fogging. First, activate the external circulation with high fan speed for a few seconds, then turn on the heater once the glass temperature balances. Regular cleaning of the AC filter can accelerate defogging, as a dirty evaporator reduces efficiency. When the defroster is on, the compressor automatically operates, increasing fuel consumption - avoid prolonged unnecessary use. Periodic checks of the heater core for blockages are also important as clogs can affect defogging performance.