Thumping or high pitch whistle through radio when raining or going through car wash.....please help

[nursejoyce]

Does anyone have any idea what would be causing my 2016 equinox to make thumping or high pitch whistle noises when it's taking or going through car was.. Dealership cannot figure it out.

 

[islandreamer]

Could the sound be from the car wash equipment itself? Did the sound continue after you left?

 

[nursejoyce]

It does it when it rains or going though the car wash when it gets wet. The dealership cannot figure it out

 

[Dpryvd]

My guess is the Antenna is amplified and not grounded solid enough. I've encountered this mostly with aftermarket radios that are installed with no ground wire. There would be a nut on the interior side of the roof just and above the headliner that secures the antenna and grounds the signal from interference. Sounds plausable... lol