Turn the air volume up or down. The switch next to the Shantui loader heater can be adjusted or turned off. The adjustment knob is used to adjust the wind direction of the left and right air conditioners. It has the function of opening and closing, and increasing or decreasing the air outlet. The loader heater valve is located between the engine main water tank and the heater water tank. The heater valve is the heater switch for the car heater.