Subject pretty much describes it. I have a float sensor that when set to gpio mode up, will be 0 when closed and 1 when open. When I change the mode to down, it should be 1 when closed and 0 when open but it just stays on 0 whether its open or closed. Float sensor is outside of tank during this test so I can verify sensor is actually changing. I am also using an ohm meter to verify the switch is actually activating and it is.
All of my code is setup for gpio down. Float sensor is setup as an "empty" sensor. When the tank is not empty, the float sensor floats up and breaks the connection, gpio 18 will show 0 - empty = 0. When the tank is empty, float sensor follows gravity and closes connection, gpio 18 should show 1 - empty = 1.
This does work successfully with down on another raspberry pi zero w, so I'm not sure what I'm doing wrong on this one. Suggestions are welcome for troubleshooting.