I’d like to know this as well. I mistakenly thought this was a standard feature. I just traded my ‘17 suburban that had it and now see the blank spot in the dash the lka WOULD have been if it was equipped. I asked chevy and they said it couldn’t be added after. Typically I don’t accept the first answer given, so I was looking on this forum for anyone else inquiring. Doesn’t seem like it would be a huge deal but finding what you want with this shortage is ridiculous.