OK, I'm going to suggest the K.I.S.S. solution here so please don't think that I am insulting your intelligence. Do you have everything set to "Auto" on the climate control with the temp set pretty low? That would cause everything to keep running to try and match the low temp.
I'm sure that you thought of this, but I just had to get it out there to eliminate that possibility.
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at or repair."
-Douglas Adams, Mostly Harmless