agshin

Hi. In my w211 Windshield wipers start before washer pump. If there dust on windshield wipers scratch the windshield. Is there way to change the working order of wipers and washer pump?

Heguli

I tried three different brand vehicles today, and all of them have that same function, wipers before washer.
Some sort of delay circuit would be needed to operate the washer before the wipers.
Though knowing how Mercedes is built, it would be rather difficult, or even impossible to build such a circuit, for a rather little use.
Override button for the washer pump, and when the rain sensor detects water it automatically wipes the glass.

juanmor40

A forum member modified his W212 wiper/washer system by adding a check valve after the fluid reservoir's pump. Once the hoses are full, the fluid should come out as soon as the wipers start moving. It takes time to move the fluid from the bottom of the reservoir through the hose up to the nozzles.

https://mbworld.org/forums/e-class-w...ml#post8419721

His solution not only works, but it is elegant. You can remove it, and return it to the stock installation. Recall that for the W211, you need to take out the right fender and be careful not to break crusty plastic; otherwise, may need a new pump/hose/reservoir.

Parts (sample for visuals), sure you can get them anywhere and you only need a few inches of tubing.

Valve: Tubing: clamps:

Heguli

Thank you! This is simple and efective modification. I didn't even remember this mod I did some +20 years ago to my -81 Chevy pick-up. Those have annoyingly slow diaphgram style pump on the wiper motor, so it pumps only when the wipers move.

agshin

Thak you for reply. I think that @juanmor40 's solutions is the best variant