If the valve of the car's heating and air pipe is broken, it cannot be replaced. The car's warm air is the engine's cooling system, which uses a small fan to guide the heat into the car during the process of dissipating heat to the engine. When the warm air is turned off, the fan stops and the hot air vent is closed, and the heat generated by the engine will disperse into the atmosphere. Therefore, without a heater switch, the hot air vents and fans cannot be turned on, or the hot air vents and fans that have been turned on keep running. When summer comes, the air conditioning system and the heater system run at the same time, which consumes fuel and causes no cold air.