Multimeter out discovered wire in most inaccessible position was disconnected not sure how or why..... remade cable tied so it cannot pull out again. Dartmouth for coffee this am on coast road temperature was constant. Still losing some water to just below min level in expansion tank and no further. Next weekends investigation, just relieved that fan now cuts in when it should.
I know it sounds obvious but is the header tank cap working corectly? If the pressure reliev spring is weak it will vent.
