preowned 2014 Bounder..still discovering things

Above the driver's side front window is a cord/wire that hangs down with what looks like a small black button on the end. not in any manual. Anyone have a clue what this may be for? dealer did not know, previous owner not available to ask.
thanks,

Toni, spouse unit..

Can you post a picture ?

I have a Fleetwood Discovery, and had something similar, it ended up being the entertainment/stereo antenna, but it didn't have a button.

I have 2016 Bounder and in that area there is the sensor for the AC/heat/Zone 1. Not really a button but sort of looks like maybe what you describing. But would think the dealer would know. Only other thing is the small mic for the hands free telephone etc.