Planning the next
AO Silver Member
Join Date: May 2007
Location: United Kingdom
If you have a Phase 1, then this may be how they're supposed to work.
Early cars had a weird system where there were two park positions. There is the off position very low on the screen but when switched on whether on continuous or intermittent, the stop position was further up the screen. The other odd aspect was when switched off, the wipers do an additional sweep before coming to rest in the lower park position. You'll also notice that when first switched on, on the first sweep the wipers don't go as near the A pillar as they do on subsequent sweeps.
EDIT : That doesn't quite fit your description and later cars have a different system. Can you confirm phase 1,2,3?