I have setup a truth table to control an exhaust fan based on the humidity feedback from a thstat. below is the following tt

Fan on         H L L L
Fan off         X H L L
Fan auto       X X H H
Hum FB Not  X X H L
Hum FB        X X L H
                    H L H L Exhaust Fan On
                    L H L H Exhaust Fan Off

What is happening in the Auto state ( On, Off, Auto are set by the user) the fan will never turn off when the Hum FB not goes low and when the hum fb goes high.

If anyone can provide some feedback as to why the fan won't shut off it would be appreciated