Air conditioning (A/C) button
Switches the air-conditioning compressor on or off: with it on, the air is cooled and dried; with it off, the fan still blows but the air is not dried.
What pressing it does
Turns the cooling system on or off; a lamp in or beside the button shows it is on. SEAT's Ateca manual says cooling mode cools and dehumidifies the air, works only with the engine running and above +3 °C outside, and is switched off when the engine is very hot. Because it dries the air, SEAT recommends leaving it on to stop the windows misting. The compressor takes engine power, so SEAT notes it raises fuel consumption. Hyundai's Tucson manual: press A/C to turn it on (indicator lit) and again to turn it off.
Check your car's manual: makes and models differ in what a button does, which positions a switch has and whether it works with the engine off, and your owner's manual is the authority for your car.
- What it looks like
- A snowflake, or the letters A/C
- Also labelled
- A/C; AC; Snowflake button; Cooling mode
- Standard
- UN R121 and FMVSS 101
What to check in your car's manual
Whether A/C comes on by itself with the demist button or in automatic mode, the lowest outside temperature at which it runs, and whether an ECO drive mode limits it.
Where makes differ
UN R121 allows either the snowflake or the letters A/C. Hyundai's Tucson prints A/C on the button. SEAT's Ateca calls it cooling mode, and has a separate maximum-cooling setting that turns on recirculation and cooling together. Hyundai's Tucson manual says ECO drive mode may limit air-conditioner performance.
Where the regulations list it
| Rule | Row | Function | Must be lit with the headlamps |
|---|---|---|---|
| UN R121 | Table, item 33 “Air Conditioning System”: symbol (a snowflake) or A/C | Control | Yes |
| FMVSS 101 | Table 1, “Heating and Air conditioning system”: no symbol or word set | Control | Yes |
UN Regulation No. 121 (01 series), location and identification of hand controls, tell-tales and indicators: Cars (M) and light goods vehicles (N1) approved under the UN 1958 Agreement, which includes the EU, UK and Japan. Paragraph 5.2.1: where fitted, a control listed in the table is identified by the symbol in its column 2; note 2 says the symbols are substantially identical to those of ISO 2575:2004. US Federal Motor Vehicle Safety Standard No. 101, Controls and displays (49 CFR 571.101): Cars, multipurpose passenger vehicles, trucks and buses sold in the US. S5.2.1: a control listed in Table 1 or Table 2 is identified by the symbol in column 2 or the word or abbreviation in column 3. S5.3.1(a): a control marked 'Yes' for illumination must have its identification lit whenever the headlamps are on, except on the floor, console, steering wheel, steering column or windshield header.
Good to know
- FMVSS 101 lists the 'heating and air conditioning system' control with illumination required, but leaves its symbol or word to the maker.
- A snowflake is also used by some drive-mode selectors for a snow setting; see the drive-mode page.
Other buttons under “Fans, air”
Sources
The symbol is cited to the regulation rows above; what pressing it does is taken from the owner's manuals below. Each document was read on the date shown.
- UN R121: UN Regulation No. 121 (01 series) as published in the Official Journal of the EU, L 5, 8 January 2016, pp. 16-19: table 'Symbols, their illumination and colours' checked 2026-09-25
- FMVSS 101: govinfo: 49 CFR 571.101 in the Code of Federal Regulations, 1 October 2025 edition, Table 1 (pp. 329-332) and Table 2 (p. 334) as printed checked 2026-09-25
- SEAT Ateca owner's manual, UK English, edition 06.21 (model year 2022), PDF: Heating, ventilation and cooling; Climatronic controls — Cooling mode; Troubleshooting, p. 147-149, 155 — Cooling mode cools and dehumidifies; engine running and above +3 °C only; leave on to prevent fogging; compressor raises consumption. checked 2026-09-25
- Hyundai 2025 Tucson (general market, English web manual): Manual heating and air conditioning — Air conditioning — Press the A/C button to turn the system on (indicator on) and off. checked 2026-09-25
Written in our own words; the manuals cover their own models only.