2007 Ford F150 Lariat

This thing is hanging loose under the engine. Can you tell what it is ? Is that a sensor ? Where is it suppose to be attached ?

 

To me it looks like the plug for daytime running lights. Since the truck doesn't have them it just plugs into a blank socket. Unplug it and see if the inside of the cap piece is empty. The little push pin on there usually holds it up front behind the bumper. Like I said open it up and take a picture of both inside pieces but I'd bet its the wire for daytime running lights.

 

Can you post a pic of it without the cap