Turn the knob to the right to increase the fan speed and airflow. Turn the knob to the left to decrease fan speed and airflow.
Setting the fan speed control knob to the "0" position turns off the fan.
Hyundai Sonata LF 2014-2019 Owners Manual: Air intake control
This button is used to select the outside (fresh) air position or recirculated
air position.
Recirculated air position
The indicator light on the button illuminates when the recirculated air position
is selected.
With the recirculated air position selected, air from the passenger compartment
wi ...
Hyundai Sonata LF 2014-2019 Service Manual: Main Crash Pad Assembly Components and Components Location
Component Location
1. Main crash pad assembly
...