Help needed) My central lock is acting up

[mnmnmmm_]

I'm having trouble diagnosing what the problem is for my central lock

I googled and searched it but I can't narrow it down

There are a few symptoms

1. Driver side door lock works fine except the right rear door does not lock/unlock: have to manually unlock from inside: this could be the actuator?
2. Trunk central lock doesn't work at all, I can not turn the key in any way. The keyhole is stuck horizontally. It locks and closes with driver side door lock
3. Passenger side door lock does not unlock the car, it only locks it. When I turn the key harder to unlock, I can see the door lock moving up but it won't unlock in the end

Any help would be appreciated

Thanks

[bmwman91]

The issue in the trunk sounds like a mechanical one if it is stuck.

The rest of it is either electrical (wire loom to door, central locking module) or part of the lock cylinder body is busted so that it is not hitting the switch contacts. You'll need to get into the doors either way and poke around. The "easy" thing to try is to swap in a working lock module to see if that fixes any if the problems. I can't say that I have heard of them going bad very often, whereas the lock cylinders are well known for having issues, so it is most likely those. There are rebuild kits which are fairly inexpensive, and the cylinders are not too hard to fix. Usually the only one that actually needs a full rebuild is the driver's door since it gets the most use from the key.

My old DIY shows how to deal with the driver's door lock cylinder:

http://bmw.e30tuner.com/articles_lockrebuild.php

[reelizmpro]

The first thing I would do is pull the door jamb plugs on all the doors and check/clean the pins. It's common for corrosion to occur in these areas. Then I would diagnose each door lock actuator. Central locking controls all the doors/trunk so if one door fails to lock/unlock while the others do, then you know the problem is with that actuator or door jamb connection and not usually the central locking unit itself. If the door locks but doesn't unlock or vice versa, the actuator is probably good and the issue most likely a contact issue in the door jamb. It's a pain but approach it logically and you'll get it sorted.

1. If all the other doors unlock...then yes it sounds like either the actuator or connection to it.
2. You have a mechanical problem with the trunk lock itself.
3. Sounds like the Central locking unit isn't getting the unlock signal to the passenger door. It should still unlock mechanically though unless the lock is worn.