i'm assuming some kind of sensor. someone on another forum who doesn't have auto climate control said they don't have this thing either so the assumption is its a temp sensor, although ive never seen an external temp sensor like this, or its the solar sensor described here:

 

Another thread on exactly that: https://www.northamericanmotoring.co...utton-for.html

Consensus there was that it is indeed a temperature sensor, internal, for triggering the Auto Climate Control.

 

That is an NTSB mandated crotch watcher to see how many times per mile you are texting instead of driving.

 

That's big brother watching you.
Temp control sensor