There is also an area under the wipers that goes into a drain area that should drain to the engine compartment. That box looking compartment just under the louver looking thing, has a a sealant in it. If the sealant has deteriorated it can leak to the area beside it causing water to get inside the cabin.

check out you tube ken bergsma he has tons of instructional videos along w/ all the help from the forum members you'll find your leak

Chasing Interior Water Leaks in Older Mercedes Benz by Kent Bergsma - YouTube

__________________