Central locking 89 corona

[Dazed&Confused]

Wondering if anyone can help me figure out whats broken with my central locking.

The central locking is only activated by the drivers door and there is a "lock doors" button on the drivers door controls.

The central locking will lock, both with the key and button, but will not unlock.

However if you leave the key in the ignition, and with the drivers door open, lock the doors with the button it will lock and then quickly unlock (I guess a safety feature so you dont lock the keys in the car).

Can anyone shed some light on what part I need to replace?

Took the door card off the drivers door, all the wires seem to be intact with no corosion or water damage on wires, switches or actuators.

Im sure you all know its very annoying! Thanks in advance