At constant RPM it could sound like a dead capacitor in a voltage regulator. Does the frequency varies with the RPM? Otherwise it could be a coil of some kind - in any electric motor, relay, valve...
Frequency does not vary with RPM. Just a constant whine. However, sometimes take it out for a drive and there is no noise. It is annoying so trying to figure it out. Will try the battery reset.
If the whining comes from the speakers then it's likely a ground issue with the amplifier. However (in my little experience with this) this results in a whining pitch that follows the RPM... so I would exclude this.