4wd switches on transfer box on 94 Fourtrak


Does anyone know which switch i need,the blue or the white one.
My problem is it wont disengage from 4wd unless i go under the jeep and disconnect the pipe going to the diaphram cylinder cover.
Basically whats happening is that im always getting suction from this pipe when pressing the 4wd/2wd button so i understand one of these switches is not working by stopping the negative pressure getting to the diaphram