Juddering Wipers !!!
That's right, the relay on the wiper motor can cause this, but I recently discovered another thing which causes the juddering....
....a very worn wiper mechanism !!!
My wipers would judder like most peoples here until I recently replaced my very worn (loads of play in all the joints etc.) wiper mechanism with one I got from Tim Hayes.
Since fitting the wipers have not juddered, not even thought about it. The action is as smooth as a babys bum.
Incidently, I see from paperwork I got with the car that my wiper motor was replaced with a new one about 2 months before I bought the car. Presumably to cure the juddering.
Just thought you guys might like another angle....