I've just noticed there was something dangling down from my car, on the passenger side near the rear wheel. On closer inspection its some sort of sensor thing which is attached the underside of the car with an arm that connects to the rear subframe. Presumeably when the subframe moves with the suspension (I think i'm using the right erminology here) the sensor also moves and soes.... something.... However it's no longer connected and the arm is just dangling down. I've started the car and waggled it around but no light on the dash come on or anything. Any ideas anyone?