Hey 52niner me agian   I also have the sound as if the APU is running when everything is off so I have a feeling thats on the list to fix.  I did want to give you a little tip though with loading the 757 cold and dark.  I have found when you load the cessna make sure all masters are off and everything is how you want it. Just go to "save flight" save it under a name like "test" and then before you push save at the bottom click on "set as default" then save the flight. and close MSFS.  when you open it next time just load the 757 right away and it will be cold and dark from then on. this way you will not have to keep loading the cessna each time you want to fly the 757.  hope this helps

-Travis

Thanks for the Tip.

Are your cabin and logo lights on even with everything powered off? Thanks a ton

Just Checked.
With everything off, no lights. Everything disconnected, battery bus, gen ties.

Thats the problem I am having, I found that just for testing purposes that if you load the cessna and shut off the master and ignition then load the 757 the noise is there but stops after several minutes.

The rest of the noise is ambient. But the Logo lights and cabin lights just really take away from the realism of the A/C , I could live with it but hope they fix it.