This high-pitched noise is on for 3 seconds then off for 3 seconds and then back on the 3, off for 3 - intermittent like that - for as long as the car is on.

It is not coming from the engine compartment. It is on whether the A/C is on or off. We have tried to see if it stops or changes if you turn on/off various things in the car. You can hear it even if the radio is playing (obviously not, if you turn up the radio volume enough).

It seems like it is a beacon - as if the car is searching for a Bluetooth or WiFi signal to connect with.

The Service Advisor has listened to it, and put his ear close to various components. He has ruled out the engine compartment and the A/C. The Service Advisor agrees that it seems to be coming from somewhere near the media controls in the center console. He has not run into this problem before and is as baffled as me.

This is like a Chinese water torture. Any suggestions to resolve this will be greatly appreciated.