new presure tank presure good for three months today presure dropped 20psi
so today i put new presure switch and presure gage to be sure that it wasn't
them still no presure gage is at 20psi switch don't kick on or off??????
Where is your pump; in the well or not?
Is the pump running?
If so you have a serious leak or some kind of blockage, maybe the pump inlet, or the pump is bound up etc..
If the pump isn't running, are you positive you have the switch wired correctly? Is there power to the switch, check breakers or fuses and any switch. If there is power to the switch, is there power to any control box, do you have one? If not is there power at the well? If you have a control box, is there power at the well? If not you probably have a bad control box.
If you have power to the well, then check amps and then shut off the power and check ohms and conductivity of the power cable and windings in the motor.
http://www.franklin-electric.com/business/WaterSystems/service/AIM/page-43.aspx You can find ohms, amps and such on a different page there.
If you don't know how to check all that, you need to call a pump guy or well driller or only a plumber that is capable and willing to pull the pump if it is in the well.