Is it necessary to turn on the AC for defogging?

[SanJason]

It is necessary to turn on the AC. Here are the relevant introductions about defogging: 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 turning off of the AC, while others do not. If the AC is turned off in defogging mode, defogging can still be achieved, but sometimes the effect may be worse. The AC button is for turning on the cold air conditioning, while warm air conditioning is used for defogging. The AC button is the switch for the air conditioning compressor. In summer, when using air conditioning, the AC button must be turned on, that is, to turn on the cold air; while warm air only utilizes the internal heat circulation of the car and does not require the air conditioning compressor to be activated at all. Therefore, turning on the warm air only requires adjusting the air conditioning button, without the need to turn on the AC switch.