So I may be getting something less than a 4 amp draw when the battery is connected to its ground cable, without the resistor in between. But whatever the draw actually is, it must be pretty high, because it kills the battery within a couple of days or so. Not sure it's worth investing in a high-end VOM that reads up to 10 amps just to pin down the exact value of the current draw.

If I find that there isn't significant current draw across the connectors for fuse 27, does the wiring diagram you have give any indication as to possible sources of the current draw upstream of the fuse? I agree that it would be good if I could eliminate the large array of functions controlled by the GM.

__________________
2003 X5 4.4i
1992 Porsche 968
2007 328i
2014 Subaru Forester XT