Hey Bob - sorry for the delay, busy, but I was all set to assist on the wire situation on '78's and took a peek @ ours and it is pulse w motor mounted in bottom of fluid reservoir...
Funny thing is, I never count on using washer fluid on these non-daily drivers for various reasons associated with little or no use over large quantities of time. Systems dry out, etc.
Ours is basic 3-speed wiper switch and was surprised to find pulse option...and you'll enjoy that our original wiring harness is not connected to the washer fluid pump!
I remember back in the day, the pump washers were notorious for leaking, reservoirs cracked and leaked, etc.
BTT