I own a 05 XJR. Today I had a new headliner installed. When I picked up the car the installer pointed to a inch by half inch black gadget above the front passenger's door. The wire from it runs down the center post and then along the floor toward the dash (wire hidden). He did not know whether the gadget (I suspect a monitor of some sort) should be inside or outside of the headliner. Seems to me it might have hung on the outside by the top of the center post but I was not sure I ever saw it there. Anyone know what it is and whether it should be inside or outside of the headliner?

Thanks!

 

Pic is gonna help tremendously here.

 

Could it be the ultrasonic person sensors for the air bag system? Behind the headliner I think.