This is probably a separate issue. Most 190e's with the 2.6l engine are known to be rather troublesome in cold, and wet weather. As I live in Maine, we get a lot of that... The most common solution is to replace the cold start sensor. This will keep you from having to give your car a shot of starting fluid every time you want to go somewhere.
The voltage regulator for a 300e Mercedes is mounted on the rear of the alternator. The regulator is a replaceable item, independent from the alternator.
Inside the alternator
The fuel pressure regulator on a 2002 S 430 Mercedes Benz is located in the fuel pump. This is a very important part of your car as it regulates the amount of fuel that your engine takes in.
where to find electrical diagrams for starting system on mercedes 300sel 1989
replace blower regulator
Under the dash on the passenger side. Easy access.
its under globe compartment, remove screw attach to the cover, and you will see wiring harness. that's were the regulator located unscrew and replace it.
The one that isn't driven.
It's under the passenger side under dash paneling. Their should be two or three screws you need to remove to get the panel down. You'll see the electrical plug going to blower motor. Remove the blower motor cover and you'll have access to blower and regulator.
it is located under the glove box. there is a black panel with four screws, take those off and there is a box with slide lockes, open it and the blower moter and regulator switch are there.
http://www.tmcpubl.com/mercedes.html
I have a short in the instrument clusters and turn signal. I need an electrical schematic for a 1980 SD diesal Mercedes.