Today I pulled fuse 5 in the trunk. Now I have no "vacuum cleaner hiss". It's a great mod that has been mentioned in other threads. the only issue I (and others) have noticed is the loss of the "beep-beep" sound when I plug the charger into the Volt. No biggie. 
The car is now whisper quiet!
http://gm-volt.com/forum/showthread.php?284306-How-to-disable-the-noise-maker
The car is now whisper quiet!
http://gm-volt.com/forum/showthread.php?284306-How-to-disable-the-noise-maker