What is the function of the car A/C button?

[VanIker]

The car A/C button is the switch for the car air conditioning cooling function. When this button is pressed, the compressor of the car air conditioning system will start working, and the air blown out by the blower will be cold. For example, during hot summer days when you need to lower the temperature inside the car, press this button and then turn the temperature selector switch to the blue section, and cold air will start blowing out. Reasons why car air conditioning may not blow air: Blower failure: The car blower is a crucial component for air output in the car air conditioning system. If the air conditioning compressor fails during use, the car air conditioning will definitely not blow air. Clogged air filter: The air filter is a significant and common reason for the air conditioning not blowing air. During operation, the car air conditioning system absorbs many impurities from the air. Control system failure: It could be due to a malfunction in the air vent, air conditioning computer, or control switch. Generally, control system switches do not fail often. It is recommended that car owners visit a 4S shop for inspection, as this will make the troubleshooting process simpler.

[Brielle]

Last time I drove in the rain, the windshield fogged up completely white. I quickly pressed the A/C button, and the cold air blew away the fog. This button actually controls the air conditioning compressor, which must be turned on for cooling in summer. Many people think it's only for cooling, but it's also essential for dehumidification and anti-fogging in winter. After pressing it, the A/C light on the dashboard will illuminate, and the compressor starts working to squeeze moisture out of the hot air. However, note that activating the compressor consumes a bit more fuel. For short trips where dehumidification or cooling isn’t needed, turning it off can save some fuel costs. If left unused for long periods, the compressor’s seals may age, so remember to run it for 10 minutes each month for maintenance. By the way, with automatic air conditioning, you don’t need to press it manually each time—it starts and stops automatically when adjusting the temperature.

[CarlosFitz]

The button on the car dashboard with a snowflake or the letters A/C is what I call the air conditioning compressor switch. Pressing it activates the cold air from the AC, while leaving it off only allows natural air or warm air to blow. The principle is that the compressor cools and dehumidifies the hot air from outside before sending it inside, which is why it cools down quickly in summer. However, many people overlook its dehumidifying function—when the windshield fogs up during the rainy season, turning on the A/C to blow air onto the glass has an immediate effect. A tip: when starting a cold engine, don’t rush to turn on the AC; wait until the engine warms up before activating the compressor to reduce the load on the engine. Owners who have upgraded to an aftermarket infotainment screen should note that some systems may hide the A/C control in a secondary menu.

[IanRose]

New car owners often ask me what the small button next to the gear lever does. It's actually the master switch for the air conditioning compressor, which drives the refrigeration pipeline cycle for cooling and dehumidification. To stay cool in summer, the A/C light must be on. In winter, you can turn it off when using the heater, but you'll need to turn it back on if the windshield fogs up, because the combination of hot air and A/C provides the best dehumidification effect. Nowadays, electric vehicle owners have it easier—unlike us gasoline car owners, who see fuel consumption increase by 1-2 liters when the A/C is on. However, there's a trick for fuel-powered cars: the air conditioning works better on highways than in the city because the compressor runs at higher speeds.