I own a 2002 CLK 320 Convertible.When the engine is running, the windshield wiper will not quit after I either push the washer button or turn it on by twisting the switch. However, they work normal with the key in the ignition and the engine off.

What I have done so far:Replaced the switch and also checked the fuses, wiper motor and motor parking sensor.

Could it be one of the relays? How would I go about testing them? Any other thoughts? Thanks in advance for your help.

 

I've got the exact same problem that just started today. Have you found any help yet?

 

What year/model do you have? Nothing yet. Its very odd, considering the wiper works fine when the engine is not running. I am going to try the relays, but I'm not sure how to test them. My plan is to go to the MB dealer, buy them all, and replace them one by one to identify the culprit. Once I identify which one is bad, I'll replace that one and return the rest to the dealer. I'll let you know if this works for me.