What does the switch next to the warm air of the hill loader do?

The air outlet is adjusted up and down. The switch next to the warm air of the hill loader can be adjusted or turned off, and the adjustment knob used to adjust the wind blowing direction of the left and right air conditioning outlets plays the role of a switch, and the air outlet is adjusted to a small extent. The heater valve of the loader is located between the main water tank and the heater tank of the engine. The heater valve is the heater switch of the automobile heater.