Just tired it and it worked
We couldn't believe it. We disconnected the negative terminal form the battery for about 2 minutes reconnected and everything works fine, so far. Will let you know if we have a recurrence like "frabuk" below. By the way the post below by "carsqwerty" is consistent with whatweI saw on some tightly bound wiring as we were working to solve this problem. If this recurs we'll be taking his recommendations next and separating the wires in some of the wire-bundle locations.