2018 3.5 XLT 77k miles. Just developed an intermittent electrical sounding buzz coming from inside the dash, both sides. Does not sound like a wind buzz. More pronounced at high speeds, although sometimes at lower speeds as well. Does not appear connected to the A/C or radio operations. Any idea where to look? Hate to pay the $190/hr shop fee if I can fix. Thoughts?

 

Sometimes a cabin air filter can vibrate if not correctly installed..

If vehicle was parked under trees and leaves get into the air intake, they can make a rustling noise.

Could it be originating in the engine compartment and telegraphing back into cabin of vehicle?

There are relays under the dash and one could be vibrating due to poor connection.

Two people can describe a noise differently and the person checking needs to hear for themself..

 

* Mr Hanky, I like the relay possibility the best. All others don't seem likely. Do you know what relays may lie within the dashboard? And what's the easiest way to access them? Thanks

 

Unfortunately, any in the dash module are not easily replaced.. It is a printed circuit board.

One of the things you might consider would be to try to verify / pin down if it is coming from the place you suspect and go from there.