I don't know how it is in MD, but in California the Dept. of Weights and Measures tests each pump for delivery routinely and places a seal on the pump. The penalties are severe for tampering with the pumps. To answer your question, MB used to use accurate VDO sending units before they got involved with Chrysler. I haven't experienced a sending unit from your model yet, but it is probably a cork on the end of a long wire as opposed to the air craft style units used in the past. Take your door panel off and see how the window regulator is cheaply riveted in the way Detroit has been doing it for years. In my opinion after having professionally worked on MBs for 30 years, the quality is going into the toilet.

Peter

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