[Summit20171SS]

Originally Posted by ctrlz

Don't see a magnet here. And no electrical connections to the shifter itself.

There is at least one good photo of the underside in this listing. Ebay is often better than GM parts sites for photos.
https://www.ebay.com/itm/26474747849...3ABFBMoK2e9Mhj

Its called a shift fork position sensor.

https://www.gmpartsnow.com/oem-parts...a&gad_source=1