How much info is needed on how to lock and unlock a car? Seriously,
this whole thing is being overthought. If you do not have an alarm in
the car, then the fact that the doors are still locked makes no
difference. If you did have an alarm in the car, the horn/siren would
have gone off by now.

Central locking is on fuse #27 (30A) along with the radio amp
(premium sound), OBC (if equipped) and the interior lights.

Try locking and unlocking the rntire car from the trunk. If you're
unable to unlock the passenger side door with the key (assuming the
key worked before), then the double lock feature is somehow engaged
which means the system still has power (fuse would still be good). The
trunk will operate all of the locks as well as work independent of the
rest. To completely disable the locking system, remove the drivers
(left side US models)  side kick panel (where the speaker is next to
your foot) and it's the relay module in the very bottom behind the
plastic plate. Pain to get to but somehow I doubt you'll have to go
this far.

The owner's manual is of little help ... it has unbelievably only one
paragraph reference Electromechanical Locking System & it discusses how to
engage it & that only the master key can disengage it.

Please keep in mind this is an 87 we're talking about here. Central
locking isn't tied into the ignition circuit at all in these older
models (not sure it is in the newer models either). My car (an 89
325i) will start reguardless of the locked condition of the doors. My
guess will be a fuse has gone out somewhere in the system. I'll find
my fuse table later and repost as to which one(s) I think it could be.

I do not know what you need to bypass the system.

But, if you locked the doors -- central locking system -- then managed to
get a door open, the central locking system still has control of the
ignition system, and it will prevent the car from starting. It this point,
the car thinks it is in the midst of being stolen, and it is protecting
itself.

I accidently locked the driver's side door and initiated the Central Locking
System.  Well, it took me a while to unlock the driver's side door again.
The passenger side is still locked and now the car won't start.  Question:
When the Central Locking System is engaged, will that shut down the entire
system, including starting the car?  I have at least the driver's side open,
but am surprised that the car won't start.  Secondly, what do I need to do to
disengage the whole system ... this is pain? Thanks for any response in
advance ... BMWFKK