Looks to me like a broken plastic connector. That'll likely be where your problem is. The plastic gets brittle over time and breaks off. I had a similar problem with a 540i I owned a few years ago, except in that case it was on the inlet to windscreen washer nozzle.
I suspect your broken piece is number 11 here. Should be an easy enough fix as long as you can get to the other side of it. Unfortunately that may require removal of the bumper.