Hi Dan,
I asked my dealer about retor fitting the rain sensors. The reply came back that I'd need a new screen, new module, changes to the wiring harness, etc.
When I questioned him, he admitted that he assumed that because there were no retro fit instructions on the computer therefore it was a major change.
I have the plastic oval mount on my screen with the 6 holes highlighted by etyu.
http://www.slkworld.com/63307-post2.html
Does this need any of the control optional modules to function? If so, how can I check the module is installed?
Thanks
Richard