Anybody know what this is? It it marked Siemens and it feels like it is attached to a wire at the other end, though I can't see it because that part is up above the muffler. The photo is turned 90 degrees CCW. The part is actually hanging down past the body above it (which is on left in the picture).

 

After some internet sleuthing I figured out that this is the TPMS antenna that monitors left rear wheel. Does anyone know what it mounts to?

 

Behind the rear splash shield (wheel well). I think rearward side