[thesorhus]

I have been driving my 1994 530i all around town this morning like usual. The lights were strong, all electrical systems operating (except the radio, hasn't been working for months, separate issue). I parked it, with the lights off and came back a few hours later. When I got in it almost started, the dash lights came on strong, and it may have cranked for a moment, then everything died. The interior lights, the dash lights, everything that was electrical. I can't even shift out of park because of the electronic safety release. I tried jumping it off another car, which I have had to do multiple times due to the inadequate "Lights on" display. When I hooked it up to the host car, no change. The interior lights wouldn't even give off that yellow glow.

I bought it with a bad tyranny about a year ago, replaced the battery then because it had been sitting for a while. I have been driving it for six months now and have had plenty of problems (replaced tyranny went bad, intake manifold cover vacuum leak, crankshaft position sensor, etc) but the battery has always been strong. I don't think, as the BMW dealer suggested, that the battery or the alternator are the culprits.

Does anyone know of a master relay/fuse/security feature that would turn off all electricity coming either from the battery or from the jump post under the hood? The computer display is unreadable in the daylight and I think I remember something about a "turn off your car" security feature, but I have no way of seeing what is displayed on the computer. I rarely lock my doors, but did on an earlier errand, could that have triggered something? Any help would be appreciated.