Wavey ~ you have to calibrate the sensor with Star for normal operation. Presume your problem is you can't even see it in Star?

Now that you have a Star I suggest you look up the entire sensor replacement method in WIS. Maybe you missed an adaption or something.

 

my mercedes is missing the rain sensor though it came with it. I only have the green wire coming out to attach to a rain sensor. The plug that goes into the rain sensor unit, does it come from the car or from the chassis the rain sensor plugs into? Here is a picture of mine.

 

Did maybe the previous owner replace the windshield and neglect to get one with the sensor? That's the only thing I can think of.

 

I have the sensor. It is just no on my car as I think there is a chassis it plugs into. If you look at the photo of the working one there is two cables, a green and a black one. I was wondering if the black on that plugs into the rain sensor came from the rain sensor chassis or from the car. That picture also shows the green plug going into something other than the rain sensor.

 

I found the black plug wire was stuffed under my ceiling. I got it out and it fits the rain sensor. Now I got to figure out how to get the rain sensor to attach to the windshield as the bracket that is there does not fit.