On the newer e9x's, there is no longer a dedicated fuse just for the headlight washers, so pulling a fuse won't disable them. Coding is an option, but an expensive one. If you want to disable your headlight washers on your cold weather-equipped car, all you have to do is disconnect the power connecter on the headlight washer pump that is attached to the reservoir.
There are three pumps in the reservoir, two for the windshield and another for the headlights. The one you want is closer to the front of the car on the reservoir, and has a tube feeding out of it that runs up the wheel arch to the front right corner of the car. There will be no visible codes thrown (and no shadow codes, as far as I can tell so far).
Method for getting to the reservoir:
- Remove the back portion of the RHS wheel arch, exposing the leading edge of the reservoir inside the fender panel
- Unbolt the single bolt that is holding in the reservoir within its cavity, and slide the reservoir out just enough to expose the first pump you see. This is the headlight washer pump. It is black, cylindrical, and a couple inches tall at most. unplug the electrical connector from the pump.
- Reinstall everything - done!
Here is a pic of the reservoir for reference - the headlight pump is number 4 in the picture. The other two pumps (7 & 8) are for the windhshield - don't touch those.