Jumpered the pump directly to the switch today: pump ground wire to switch ground terminal, pump power wire to switch accessory (green) terminal – pump worked perfectly with switch.
Next jumpered JUST the pump ground wire to the switch ground terminal. Did not jumper the power, reconnected the original pump power wire to the original switch accessory wire – pump worked perfectly with switch.
So… unless I’ve confused myself: switch is good, pump is good, GROUND IS BAD (as many of you have suggested).
Checked my terminal block again for corrosion and loose connections, can’t find any. Two grounds from switch to where? All the pump wires are bundled in a wrap in the bilge (very neat and secure) but difficult to trace pump ground to terminal block.
Guess you’all can tell by now, my electrical skills are pretty limited! I realize I can use the aerator pump to fill the live wells without the freshwater in pump, just like to have everything working as designed. Chasing the ground, chasing the ground……
