Can't help but wonder if you've had a bad relay, and a problem with the stalk too. Or maybe one of those problems created, and keeps recreating, the other problem.

 

yeah mtroxel, if this isn't the most odd electrical gremlin. Next is a new relay and if that doesn't fix the issue, then its the stalk. Do you know of a DIY stalk replacement write up by chance?

 

No I don't. Just be sure to disconnect the battery, cause the airbag is the first thing to come off before you pull the steering wheel. Oh, and I know a guy who forgot to mark the position of the wheel and had to mess around a couple times to get it back to straight ahead....

 

Oh, alright then. I'll keep the marking of the position in mind, if i need to change the stalk. gotta be a write up some where...

 

Bringing this back from the dead, Aside from the sparks, I have the same problem (B5 S4) where the wipers will come on with turning the key and run for like 2.5-3.x wipes then stop at some random point on the windshield, stalk is set to off during this. If I move the stalk to any of the running positions the wipers will run every 12-14 seconds for 2.5-3.x wipes then stop, and repeat.

I've replaced the motor, relay, and stalk all with new OEM dealer parts and the problem still persists. I also greased the wiper transmission but it didn't really need it, moved freely. Did you ever find the solution to your problem?

 

Old problem, but I had the exactly same issue (without the sparks - the sparks have nothing to do with it).

Issue is mechanical. Wiper motor can not find the place to stop, so it rotates four - five times and then stops randomly. You have to open up the worm screw cover and move that copper "trigger" to other location and then put back together and try again.

Then when wipers find a regular stopping place, you just open the one nut that holds wiper rods on the motor and move that to correct position (all the way to passenger side) and put it back together.

This link is helpful:
KilometerMagazine.com - DIY: A6 C5 wiper linkage re-set into the home position

 

You may want to check your Convenience Control Module under the driver's carpet. if wet, this can happen. At least it did on my B6.