2018 Q4 with Fiamenghi Ti exhaust, Race Mod, and Tecnico wheels.
The front one in my NAFTA car was cable tied off between the engine block and alternator. Very hard to find.it's for rear headlight height sensor. if you got one for rear, you should also have one for front sensor in front right wheel arch/engine bay area.
I am still working to get the headlight levelers to work on my car. Installing them and starting calibration just gets me "conditions not met". I suspect that it does not like my settled suspension, so I have ordered parts to correct that.