I've searched this forum, and seen that your guys know quite a lot about electronical problems on the Polo 9N.
- And I have a problem

I have bought a 2003 Polo 9N 1.9 TDI.
The problem is:
The windscreenwiper is very unstable - not working properly!
Description:
The wipers are fast - not slow. The speed is good, no problem here.
When I turn the wipers on, pushing the right stick downward to the spring-function, the wipers often starts. And completes a full windscreen-wipe. But sometimes the wipers don't even react to the command. They simply do not start!
I can hear how the relays are clicking - when they do work, the relays click at start and finish. When they don't work, they sometimes click at the start, sometimes not.
When they don't work, the wiper-function kind of "freezes". About 2 minutes after, a relay clicks, and I can try to activate the wipers again. Sometimes they work now - sometimes not.
If I get the wipers started, and push the right stick upwards on either "constant wipe" or "fast constant wipe", the wipers will stay on as they should. Once you've got them started, they'll stay on

Why is there a problem activating the wipers?
Solutions?
I hope some of you can help me - that'll mean a lot to me.
Ole, Denmark