BTDT.

As I recall, I was able to reposition the cable onto the eccentric pulley by rotating the pulley (both pullies) all the way to one extreme. I might have removed the wiper arms to facilitate that -- don't remember -- and this might have permitted the pulley to rotate past its normal "stop" position.

I also temporarily removed the linkage from the pulley to the wiper motor to give me access.

The small threaded shaft and nut are used to adjust the tension in the cables. I suppose one way to reposition a cable is to completely remove the tension, reinstall the cable, and then reapply the tension. I didn't face that type of problem (my eccentric pulley fell off the wiper shaft).

The whole thing was so painful I've almost completely purged it from my memory banks.
--
Don Foster (near Cape Cod, MA)