Some signs that your water level sensor is not working correctly include: 1.) The washing machine does not fill up with water. 2.) The washing machine does not sense when the laundry basket is full of clothes. 3.) The washing machine does not automatically stop when the laundry basket is full of clothes. If you notice any of these signs, it is a good idea to test the water level sensor with a multimeter. If the sensor is not reading correctly, it will need to be replaced.