You need a 12-volt test light and an inexpensive digital handheld meter to help you with minor issues like this. The alternative is to substitute via purchase or pay a hundred dollars an hour for someone else to do the same thing. But guesswork is expensive, and frustrating. Many times there are zero easy ways to test something by process of elimination using guesswork. Your panel lost supply power. Is it a fuse? Is it a burned out power supply? is it a positive or negative power feed break? The working water pump switch proves there is 12 volt power nearby. After that conclusion it's all guesswork without a meter and test light.
