AUX AC Severe Battery Drain during normal vehicle operation

[BWINFMD]

2007 Yukon XL

AUX Button randomly turns itself on and off with no human interaction.  

Severe Battery drain is occurring when the "AUX" button is "on".   

Alternator/Serpentine/AC Belts have been replaced and the symptom seemed to subside for a week or so, but has now returned with a vengeance. 

Day driving isn't so threatened, but night driving has become unsafe, headlights are constantly is some mild flux of dim strobing.

Any clue to why the electrical in this Yukon has begun to behave like Christine?

[CapitalTruck]

Rear blower motor getting ready to crap the bed?  Drawing too much?  Or something in the electrical line finding ground?