Planning the next
AO Silver Member
Join Date: May 2007
Location: United Kingdom
It's the offset park feature.
When you switch the wipers off, they park lower down under the bonnet edge than the extent of the sweep when in use. In your case ( and many others too ) it isn't coming out of the park mode.
The culprit is a little gadget near the motor. It's a round plastic dome about ( from memory ) 5cm in diameter.
It works by allowing free movement in one direction but limited travel in the reverse direction. So, when you start the wipers it allows full travel to the edge of the screen after the first wipe ( which resets the limited reverse ) and continues like that until the wipers are switched off. Then, it does a partial wipe and the motor is reversed which engages the limiter allowing the wipers to park under the edge of the bonnet. At least that's how it seems to work in the very limited amount of time I had when I looked at mine.
What probably happens is the grease inside goes hard limiting its operation. I've yet to find out how to open it up to clean it out and insert fresh grease but I've not looked too closely yet.
If you do find out how to open it up, I'd appreciate knowing.