I haven’t had a chance to revisit the odd electrical issue because it isn’t a priority as I have been trying to stop the coolant leak at the thermostat housing. There is corrosion in the aluminum head which was fixed once years ago but it’s back now! I tried to use multiple gaskets in addition to the form-a-gasket sealer which I thought would fill the irregularities but does not.
What I tried today was to put some sealer into the deepest pits, leveled it, then let it sit. Then I applied a coat to the bottom of the gasket, which this time is the heavy cork type, and applied it, putting the housing on without tightening,