I'm well versed on how to use a multimeter as I worked as a service engineer for over 40 years for a medical imaging company.
All the fuses I can find have checked out good with the meter. Perhaps a latching relay that is activated/deactivated. The 3 different switches are momentary switches. The water pump light is supposed to come on and stay on until and one of the 3 switches is pressed, then the light goes out and there is no longer a light and no power to pump. Anyone have any clue as to where the latching relay would be located if there is one?