You say your gray tanks fills up on its own and I assume you understand that this is not correct. The gray tank fills up due to water being sent to the gray tank. I would start the investigation by making sure your fresh water tank is full, disconnecting from the city water connection and ensuring your water pumps are turned on. On the assumption that your black and gray tanks are empty when you start this test, what, if anything, happens when you are in dry camping mode? Do you hear the water pumps cycle? Is your fresh tank water level dropping while the gray tank level is increasing? Is nothing happening?
