[dtengineering]

It is possible that your code is correct, but the pressure switch is not working properly... not likely, perhaps... but possible.

Have you tried checking the pressure switch with an ohmmeter to see if the contacts are closing and opening?

Alternatively, have you tried hooking up a switch (or just using jumpers) on the i/o pin to see if your code can read a "known good" switch?

You probably have, but just thought I'd add a "check the hardware" comment in amongst all the helpful software advice.

Jason