Strange rear wiper behaviour with new motor

When I bought my W164 some months ago the rear wiper motor was not working and was stuck according to previous owner. So I bought new motor (not Original, but came up with the same partnumber as it aparantly is used in many other cars, chryslers and so on). 

So no problem changing motor but it works in a funny way. It only moves around 1/4 of the way when it is on, have to wait 10sec so it moves again 1/4 or turn OFF and the ON 5 times for the wipers to travel the whole way. But when I use the window washers, then the wipers move like they are suposed to. I have changed out relay P and S but no luck.

Anyone have any idea? 

 

See video of behaviour