2005 Maxim 3.5 sl
makes humming noise even after engine is off.
Noise is coming from from passenger side.
I disconnect batter noise stops, as soon as I reconnect battery noise starts again. Noise lasted for over 8 hours while I was at work. Did not drain battery.

Any suggestions. I'm thinking maybe waterpump, since this runs while engine is off..

 

The motor mounts may be electronic?
Check the hydraulic mounts.