Thanks for the info! I think we're getting somewhere. I disconnected the big cable in the passenger footwell. The draw only occurs between the battery and the feed line to the trunk panel when fuse 5, 6, 11, 15 or 16 is fitted. 5 and 6 are for power windows, 11 is for the convenience module, 15 is for ATA(?), IRCL(?) and rear headrests, and 16 is for the stereo. Now to find what they have in common...

Sixto
93 300SD