wind shield washer fluid pump
 

98 CLK 320. I have one of those incredible situations where the washer pump empties the contents of the washer fluid onto the windshield nonstop, until the container is emptied. It happens only when the car has been parked in the rain - not when driving in the rain - for a few hours. It starts when I turn the wipers on. Once the car is "dry" again, the system works well.

I have had the car checked for faults, on the dealer's OBD, no faults came out, only garbbled messages. I have had the grounds checked with no issues. I have had the pump assembly checked for cracks or leaks that would enable an electrical short: Visual check do not show any issues...

Can any one with a similar problem give me a pound of wisedom ?