Steve, thanks again for your help. I found this on the Turbo Buick’s site.
Generally it's the $50 wiper cover that needs replacing.
Wiper washer with pulsed wiper application needed.
If you pull that cover off when the wipers are down and near parked you may find the mechanical arm isn't engaging correctly or disengaging actually to help park the wipers.
The mechanical arm has to fall into a detent in the wheel in there to park the wipers (turn them off).
You might be able to take off the cover and lube the arm/wheel or see if anything is broken in there.
The arm moves into the detent and should kill power to the motor when it works right.