I have a Prius 2017. on a couple of times an internal, a continuous, high pitch alarm noise starts, apparently with no reason, while driving. The sound seems to be from an electric relay in the dashboard. It does not come from the car alarms nor from anywhere in the hood. it does not stop even if I turn the car off. The only way to stop it is to briefly disconnect the (-) battery. Once the noise stops, I reconnect the battery and the car seems to function normally.