Push the OFF button of the front to turn off the air climate control system. You can still operate the mode and air intake buttons as long as the ignition switch is in the ON position.
Hyundai Elantra AD (2016-2020) Service Manual: Passenger Airbag (PAB) Module Components and Components Location
Components
1. Passenger Air Bag (PAB)
...
Hyundai Elantra AD (2016-2020) Owners Manual: Instrument Cluster Control
Adjusting instrument cluster illumination
When the vehicle's parking lights or headlights are on, press the illumination
control button to adjust the brightness of the instrument panel illumination.
When pressing the illumination control button, the interior switch illumination
intensity ...