If your door latch is not working properly, the first thing to inspect should be the door catch. The door catch is attached to the top of the dishwasher tub and is normally adjustable. If not adjusted properly it can cause the door latch to not activate and will prevent the dishwasher from working, or it may not close the door tight enough to prevent a leak. The door latch may also be worn and no longer creates a tight fit, in which case the door latch will need to be replaced. The door switches may also cause the door latch to not work properly. The door switches may have no continuity so an electric circuit cannot be completed to the controls. If you think the door switch may be the cause of the problem, you can test them using a multimeter.