I suspect the two problems are related, but perhaps not. Need to get to the fuses in the trunk to check. Is there a manual release somewhere? Ideas on fixing the window issue? Thanks for this forum.
This may be of general interest - http://www.8coupe.com/Home.aspx The ETM here might be of some help - http://wedophones.com/Manuals/BMW/ I took a quick look at the '92 850 ETM - presuming other E31's are similar, fuses 1-29 are in the front fusebox, the others are in the one in the trunk. The following pages were details and wiring diagrams for each fuse, so maybe taking a look at which fuses affect the windows & trunk and their wiring diagrams will lead somewhere. The repair manual here is worth having the link just to refer to generally: https://www.bmwtechinfo.com/repair/main/index.htm There were a variety of places for owner manual downloads, this one was a straight .pdf so I figured it's less likely to be malwared - https://carmanuals2.com/get/bmw-850i-coupe-1989-owner-s-manual-17627 Note the mention in the owner's manual of the trunk locking when you lock the glovebox, so maybe check the glovebox is unlocked. It appears you can manually unlock the trunk with the key (perhaps only on earlier E31's though), it looks like the trunk latch button may be keyed. One of the problems that came up on the 80's-90's BMW's with manual locks was the double-locking feature after x-many years of wear & tear on the lock cylinders. Once they were worn enough, you'd have no lock détente at the normal locking position and the key wouldn't stop there, instead turning all the way to the double-locking position, and if the lock cylinder wasn't replaced, eventually you'd get stuck locked out with the doors deadbolted since the lock was too worn to unlock the double-locking. If the 850 had remote locking and that was used primarily vs. manually with a key, then you'd think there shouldn't be significant wear factors as far as the mechanical locks go. Hopefully you have nothing like that, but also make sure it's not double-locked, that presumably might lockout the manual trunk latch release. It's not unheard of for those driving bimmers with the double-locking to religiously only lock the car by the keyed trunk button, which can't engage the double-locking. It's always a good idea to replace a worn lock cylinder on any older higher-mileage BMW with keyed locks once such wear is noticed. With the 850's downward-facing trunk button, it's obviously not so convenient to use in lieu of the door's lock. Note parts 15 & 19 here, would seem to indicate some were keyed, & some electronic, so maybe early ones were keyed & later ones weren't. If you don't have a manual push button to release I'm not sure what the other routes/options are, but surely there must be something! http://www.realoem.com/bmw/enUS/showparts?id=EF63-USA-05-1994-E31-BMW-840i&diagId=41_0087
Thanks! I was able to get the trunk open. The windows are still misbehaving, the passenger side works, but now the driver's side do not. I replaced some fuses. The cigarette lighter socket is also intermittent.
