2009 Vue with Honda 3.5

[2009Vueguy]

I have been a car guy for maybe 50 years, repaired many different models, even had my own shop for a while.
My 2009 just developed a strange problem. There is a whining noise from under the coolant expansion tank even when the
key is off. An electrical fault perhaps? Only shuts off when I pull off the battery cable. Strange. Maybe a relay malfunction?
Guess I will pull out the expansion tank and see what component is located underneath it. Can't seem to find it in my
Haynes manual. Car has 150k miles.

 

[Derf]

Can't find it in your vue Honda V6 manual because it is a GM 3.5 not a Honda 3.5 which they stopped using in 2007.

Wild guess is the air injection system is stuck on but I really have no idea