Hi Jwalter! The middle button should be the mirror dimming button. On page 431 of the most recent manual on mopar.com it says the following:
"NOTE: The Automatic Dimming Mirror feature is disabled
when the vehicle is in REVERSE to improve rear view
viewing.
The Automatic Dimming Mirror feature can be turned on
or off using the Mirror Dimming Button on the mirror."
Hope this helps!
Kori
Chrysler Social Care Specialist