Is the pump above ground or in the well?
Assuming a submersible pump, the wires/cable leaving the switch, do they go to a box and then out to the well? Or just out the the well?
At the well, can you hear/feel the pump running?
If the cable/wires go out to the well (no box), do you have power at the well (remove the cap and there probably are wire nuts. You are fooling with 240vac so shut off the power until you are ready to test for voltage.
You have a low producing well or you wouldn't have a switch with the lever on the side. You do rotate the lever to the Start position and hold it there and the pressure gauge stays at 0 right?
You can do ohms and short readings, go here: