central locking problem trunk/boot won't unlock 1994 4-door e36

Are you using the valet parking key? This will open everything except the boot lock!

one key opens everything unlocking the driver or passenger door also unlocks the boot it is not a button type lock is actually a key and door lock the lock on the boot just turns

I don't knoiw about the central locking, but it sounds to me like you are trying to unlock the trunk using the Valet Key. The valet key will not open the trunk, and if the trunk is locked the right way, it won't respond to the central locking anyway.

Your E36 is different than everybody else's.

When you find a key that fits the trunk, you notice that it can be turned either left or right, then back to the center. If turned to the right, the trunk will be locked all of the time, and will not respond to the central locking. If the key is turned to the left, then the trunk will lock and unlock via the central locking.

i've been the owner of this car for 2 years the trunk has always locked and unlocked at the same time as the rest of the doors. it has only been in the last 6-8 weeks that the boot/trunk has not unlocked any other ideas there is definately only 1 key which when placed in the driver or passenger doors locks and unlocks everything

Faulty central locking motor, wiring, or the lock needing cleaning/lubricating.