If you cannot fix it - what I did when I really did not use them was I took the wipers off, put grease on the threaded shaft and installed a red wire nut on the shaft.

Hi Nailbender,

Are you an apprentice carpenter, or maybe you work at Guantanamo Bay?

I'm using the late model 850 schematic, prob OK for S70.

How to check wiring:
The Black wire at the driver headlight wiper connector needs to connect to the battery Negative. Check with your ohmmeter that you have a solid connection.
Maybe your ground lead crapped out?
Check other two wires for +12V DC.

The piggyback wires at the battery terminals need occasional attention.
Pull them all off, shine them up and reinstall with Penetrox-A or conductive
grease (copper or nickle anti seize)
Look for loose or corroded terminal ends, and repair or replace.

Good luck, Bill