I tried a VIN lookup to discover the color of the car's original windshield.

http://www.mercedesmedic.com/decode/

Didn't say anything about the windshield.


I had the windshield replaced and the rain sensor does not work.

An unknown is the color of the original glass. There are two possible rain sensors, depends on if the glass is green or blue.

How can I learn which was original with the new car?

__________________
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1st MBz: 1982 300SD
2nd MBz: 1987 300SDL
3rd MBz: 1995 S420
4th MBz: 1987 190DT
5th MBz: 1984 300SD w/1983 300DT engine
6th MBz: 1999 C230k I'm 3rd owner, got it w/57,235 miles.
and manages Mom's 2007 R320 CDI

What kind of car? Glass shade colour usually doesn't matter. If the rain sensor isn't working I would be looking towards the rain sensor itself not being installed properly. Most glass shops try and reuse the gel that's applied to the sensor and some don't even apply any gel whatsoever.
Most Mercedes in my experience have blue shaded bands up at the top though.

1999 C230k, Elegance. I read the Mercedes C-class can have either green or blue glass, and there are two different rain sensors, one for each. If the wrong tint windshield is installed, the rain sensor must be replaced with the correct one.

__________________
.
1st MBz: 1982 300SD
2nd MBz: 1987 300SDL
3rd MBz: 1995 S420
4th MBz: 1987 190DT
5th MBz: 1984 300SD w/1983 300DT engine
6th MBz: 1999 C230k I'm 3rd owner, got it w/57,235 miles.
and manages Mom's 2007 R320 CDI