I have a second home in northern Michigan. Usually I just shut off the pump when I leave to go back to the big city but this year I not only shut off pump but also opened taps until water stopped to prevent broken lines in the event power went off and interior temps dropped below freezing. This past weekend, I powered up system and turned on pump with faucets open until water ran. Noticed pressure was much higher. Also noted I could never hear pump cycle off as usual. Not a good thing, so I started shutting off power to pump unless we were using water. Is the problem with the pressure switch (outside in the well housing at ground level) or becaust I let all water out of pressurized tank? Pump is 160 feet down. Help please.

If you have a 30/50 pump, then your pump should cut off at 50#. If it does not, then suspect either the switch is bad or the little pipe leading to the switch is clogged up. Check your gauge and see how high the pressure is going.

Could it be that the water in that little pipe is frozen? And that next time I get up there (assuming the weather warms) that all will be well? Would it be worth putting a light in there next to the switch and pipe?

If the water in the pipe is frozen, then your switch would not be able to "sense" pressure increasing and would not cut the pump off. Never heard of that happening, but it is possible. Yeah, I'd put a light or even a little space heater in there.

Also possible that the switch froze. There is a little flexible diaphragm in the switch that the water pushes against to allow the switch to work. Could have been damaged.