Rear Window Defroster

The defroster heats the glass to help remove frost, fog and thin ice from the rear window with the engine running.
To activate the rear window defroster, press the rear window defroster button located on the center panel switch panel. The rear window defroster button indicator illuminates when the defroster is on.
If there is a heavy accumulation of snow on the rear window, brush it off before operating the rear defroster.
The rear window defroster automatically turns off after approximately 20 minutes or when the ignition is turned off. To turn off the defroster, press the rear window defroster button again.
Outside Rearview Mirror Heater (if equipped)
If your vehicle is equipped with heated outside rearview mirrors, they will operate simultaneously when the rear window defroster is turned on.
Test yourself
A quick Hyundai Tucson LM quiz: every answer comes with an explanation and a link to the manual page.