I was driving East bound on I-10 in southwest Arizona at about midnight at 75 mph with cruise control when both headlights suddenly went out; visibility was suddenly zero. I pulled back on the bright lever and my brights came on giving me vision. I checked the lights knob and the lights were turned off. I turned the lights on and they functioned normally. On analysis later I think when I moved my flexed knee toward the door my knee contacted the lower part of the light knob and turned the lights to the off position. The lights knob is lower and closer to the center compared to other previous Tahoe I have owned making it easier for the driver's knee to make contact with the lights knob so the lights can accidently be turned off. I solved the zero visibility in a few seconds. If it would have taken me 5 or 10 or more seconds I could have been killed. Drivers of this 2021 Tahoe should be warned that their knee could turn their lights off and that if that does happen pulling the bright lever or turning the light knob back on can correct the problem. In the future this light knob should be changed; putting it higher and more toward the door would be better or anywhere it can't be accidently turned to the off position. This is extremely dangerous and people could be killed! please warn the drivers of the 2021 Tahoe and any other vehicles with similar light switch designs and make corrections with the light knob in the 2021 Tahoe and vehicles with similar designed light switches.

- Phoenix, AZ, USA