Re: well/pressure switch
The thing you need to determine is if the contacts in the switch are closed (making contact) when the pump is not running but should be. In most pressure switches, the cover is removable and the contacts are visible. Be careful you don't touch the live electrical parts of the switch.
Is the pump an above-ground or submersible pump?
The pressure switch has a rubber diaphragm between the inlet and the mechanical linkage. If you've got a lot of sediment or scale in your water, sometimes that can build up between the base and diaphragm and prevent operation. You could carefully disassemble the switch and see if this is the case -- also check the tiny hole in the base that lets the water into the diaphragm chamber. If you poke something into the hole to clear it out, be careful because you could rupture the diaphragm.
If you find out there's junk getting in there, make sure the switch is mounted so that the pipe leading to it is vertical with the switch on top. Lengthening this pipe may help.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.