what year Acadia is this of yours? My 2019 does it alsoSo, while poking around under the hood trying to see if I can fix my AC line, I noticed that after I turn my Outlook off, I get this quiet high pitched, vaguely electronic sound followed by a clunk, then it repeats. Sort of 'Wheeeeeeeeeeeeee-katchunk Wheeeeeeeeeeeeee-katchunk'. It sounds like it's coming from up under the base of the windshield, at the firewall. I don't see an obvious source, though.
I also seem to hear the high pitched sound while the engine's running too.
Is this normal and I've just not noticed it before?