2016 GMC Sierra 2500 HD Fog Lights
 

I have a new (to me) Sierra that has fog lights installed. I feel really dumb, but can’t figure out how to turn them on. I consulted the owner’s manual and it said to press in on the center of the head light knob if the truck is equipped. There is nothing to press here. Stumped
https://cimg4.ibsrv.net/gimg/www.tru...c54491423.jpeg
https://cimg8.ibsrv.net/gimg/www.tru...6bf0bd400.jpeg
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