weird connect a switch to the sensor's/pumps wire lines and see it if works. if it does it might be the game is lagging and you are not seeing things as the happen as lamps and gates can switch on and off really fast to fast to notice. i had that happen to me with gates and such. i should also say that friendly NPCs might be able to open and close those gates like they do with normal doors but im not sure as i dont use them much.Edit: There's also the problem that my current airlock worked perfectly yesterday and now none of the Lamps, Logic Gates, and Player Above Sensors simply do not detect me AT ALL. I dunno what happened.. ;-;
Edit 2: Wtf, I opened the gate to see if the pumps were at least working, and the water just stayed in place like it was made of gelatin lol. But really, wtf.
edit: oh i remember i had a problem with my timers not working at all before i just remembered. check to see if that is the problem wire a torch to it that way you can see something obvious turning on and off. you might have the same problem as me though it dont know what makes that happen or how to fix it. for me it came and went on its own