Looks like you have a low pressure cut out switch a good idea. You must get a new pressure gauge yes.
Sears 390 2514 390 2518 Troubleshooting Chart
Well pressure switch stuck closed. Access the switch mechanism by removing the cover to the pressure switch. Pull the contacts apart and dislodge the internal spring. Shut off the electricity to the well pump system. If the switch does close you can turn the power back on. Turn the top screw cap in a. If the pressure control relay switch closes and turns on the pump after you tap on it but if it otherwise sometimes sticks in the off theres probably a problem with the pressure control.
Check the water pump breaker in your electrical box to make sure the breaker hasnt tripped. If the switch doesnt close and the water pressure remains low the switch needs to be repaired. The contacts on the switch are like points on an old car and can corrode and fail. Cycle the water pump. Switch off the circuit breaker or remove the fuses that supply. If you have voltage coming out of the pressure switch you need to check amperage.
Low amperage means the motor is running but the well is out of water or the pump shaft is broken. If your car thermostat gets stuck in the closed position your car will overheat quickly. Double check that power is running to your well and that there isnt a short. The pressure tank switch regulates when the well pump needs to supply more water for the load being used in your house. Regular amperage means you have a big hole or a break in the pipe. These switches are wear parts and need to be replaced at regular intervals to avoid inevitable failure.
Even with the points closed there may be no voltage getting through the switch. How to tell when a pressure switch to a well pump is gone step 1. Here are a couple things to check. Then it will hold on its own. The comment down the page about rust clogged plumbing is definitely relevant. Check the well tank pressure gauge to see if it is at least 40.
If the switch goes faulty your pump will potentially work overtime or could prevent the well pump from coming on at all. No amperage means the overload has tripped or there is a broken wire somewhere. But to get the pump to start up you need to hold the lever partway up until pressure gets to around 20 to 30 psi. If it has tripped you will.