Central locking: doors unlock and then lock immediately.
 

Symptoms:
1. In the beginning all drivers, passenger and trunk was locking/unlocking fine by key;
2. At some point, passenger door stopped locking/unlocking when I was using drivers door. Drivers door and trunk would work when I would unlock/lock from passenger door.
3. I've decided that actuator in passenger door went bad. Changed the actuator (it's another long and sad story).
4. With new actuator in passenger door, car will lock OK from the driver door, but when trying to unlock, it will lock immediately again.
5. From the passenger door car would lock/unlock only passenger door and not drivers.
6. AT this point after reading forums I've found that there is actuator for the fuel door as well and, when it bad, it might cause issues too. I've disconnected and removed fuel door actuator and waiting for replacement part, but it didn't solved original issue with locking.
7. I've installed Stellar BMW45P keyless entry system, but problem is there: car will lock from the remote but when trying to unlock, will lock itself again.

I am a little bit lost at this point what to look for. Can it be that drivers door actuator went bad since drivers door won't lock from passenger door?
Can it be that passenger door actuator installed wrong?

Or it's completely different issue like microswithces in lock?

I don't think I have enough experience with the central locking system to answer your other questions, but on my 2/93 318i, I had first the front, passenger door lock actuator, then the driver door lock actuator fail within a week of each other. It seems unlikely to read of it happening again, but then it seemed unlikely to have both actuators fail on me.

John,
Thanks for the reply. I'll try to investigate what might have happened there, first suspect - incorrectly installed actuator in passenger door.
I guess I'll disconnect it and see if drivers door/trunk will work.
Than I'll disconnect drivers door actuator and check how system will work.