Thanks for checking that for me. Bentley manuals are great - I have one for our E92, but not for the X5. OK, that gives me something else to check. I'll disconnect the connectors going to it, just like I did the the LCM, and see if that stops the current drain. It's located behind the glove box. I'll check it out tonight or tomorrow morning, and report back.

First of all, many, many thanks to Trader4 for looking up in his Bentley manual that fuse 27 protects the General Module. I disconnected mine this morning, and voila! - current drain drops down the the same level as when fuse 27 is removed. If it hadn't have been for Trader4's suggestion, I would have given up, and taken it to a mechanic to finish troubleshooting. A new GM costs over $500, but I just put an offer on one on eBay for $75. So doing this job myself, with tremendous help from this forum, probably saved me over $600, because no mechanic would replace the GM with a used one.

But there's one peculiar thing. Today, after letting the car sit for at least 45 minutes with the negative battery cable connected to its terminal through the 1 ohm resistor, the voltage reading never got down to the 38 mV reading I got the other day - today, it's reading 73 mV. So I removed fuse 27, waited another 20 minutes or so, and the voltage drop across the 1 ohm resistor is still 73 mV. Not a disaster, as it would take a very long time to drain the battery with this level of parasitic current flow, but it's strange that it's double what it was last time I checked it. Any idea what the normal range is for an X5, and why it might be so much higher today than it was a few days ago? Thanks.

I've been following this thread and have to say that I'm impressed with trader's dedication to solving this issue. I had a similar issue with a prior vehicle and lost a great amount of patience trying to find the culprit. I traded the car shortly after giving up so I didn't really have to live with the consequences.

I bought a 2002 4.4 about 3 years ago and it was my daily driver for 2 years. I didn't realize that I had a parasitic drain issue until I let my son take it to college last year. The car battery would drain if it sat for more than 2-3 days (which was common for him at school). I replaced the battery and it continued (the alternator was good). Thinking back to my last experience, and knowing he needed the car and I wouldn't have an opportunity to spend time tracking down the issue, I went the easy route and bought and installed one of these - Priority Start. I found this solution when I was researching "X5 parasitic drain" I know it's a band aid, but it got him through both semesters. When he came home this summer I planned on trying to fix it, but the Priority Start has been working so well I just never got around to it.

Just putting it out there for others that might not have the expertise or the dedication to track down the root cause of the drain.

Trader's dedication? Hey, what about MY dedication? I must have put 12 hours into this project! :D

Just kidding. Yes, I'm incredibly grateful to Trader4 for pointing out that the GM is also protected by fuse 27, which was not shown in the fuse diagram, nor did I find anything about it in any of the searches I had done regarding fuse 27. And I'm thankful to him and several others for generally following this thread and keeping up with my progress.

I've definitely learned a ton through this experience, and feel prepared to tackle future current drains, which are all too common in BMWs (and probably a lot of other newer cars as well).

Wow, I totally messed that up! I meant Multibeemer, the OP! Sorry about that. I do acknowledge that Trader turned you on to the final piece of the puzzle. :)

I'm pretty sure it's the GM, because as soon as I disconnected it, with fuse 27 still in place, the voltage drop across the resistor immediately dropped to the same value it was with the fuse removed. Including all the fuses, LCM connectors, windshield washer pump connector, radiator fan connector, and every interior and luggage area light connector, I must have disconnected over a hundred circuit elements over the past few days, and only got this response when pulling fuse 27, and disconnecting the GM.

I hope somebody else benefits from my experience. The main thing I learned was not to assume anything. Just because "lots of other people" have experienced a particular thing (like a failing FSR, for example), it doesn't mean that you have this same problem. In fact, I didn't have any of the most common battery drain causes, namely the FSR, telephone circuit (I had had this one a few years ago), or the LCM, but something that seems to be quite unusual. So, you never know until you test everything.

i still suspect a chaffed wire in the trunk lid's rubber boot - the fuse F27 indeed is supplying constant power to GM's pin 10 however, the GM is using that power to control the devices that are identified in the fuse diagram... While it is possible that a MOSFET transistor inside the GM module is blown, the GM module, like all the other ones, is a solid state device, and only entertains electrical current. the in-rush of current can blow a MOSFET, but what is the reason for the blow? it could a very brief short, and the most common place for a short in the named places would be inside the boot...

I have had a short in the rear wiper motor (the rear wiper did not work) that resulted in non-functioning adaptive lights... one would think that the two are totally unrelated but the misterious ways of electrical path rendered the adaptive lights inoperable, to the point that i was considering replacing the adaptive module (i ignored the rear wiper), until i read the error memory, and there was NO error in the adaptive module, it was responding properly... even manual controls for the lights were working... which got me into thinking about other problems, and the wiper motor was the only problem at the time, once i traced the wiring for the motor, found a chaffed power wire that was briefly touching chassis, repaired the fault and the voila! - the adaptive lights started to work... go figure...

if you can, put the car on INPA, read the errors, if GM is faulty, it will spit something, otherwise look for problem not within the GM but without...