Wrap on your pressure tank fromtop to bottom. Does it sound like it is full of water (it shouldn't be)?
Turn off the pump (cycling will kill it and the switch). Open a faucet or othervalve somewhere and leave it open.
Take your tire pressuregauge and measurethe air pressue in the tank. If you get water out of the valve, it is almost certainly shot. If you don't, the pressure should be about 2# less than the turn-on pressure of the switch.
If no water, pumpit up. Close the faucet, turn on the pump and see what happens. Watch the pressure gauge. Assuming it gets to the turn-off, high pressure, continue to watch the gauge for a bit to see if it drops on its own. It should hold. If it doesn't, your check valve is probably leaking or there is a break in the piping.
