E30 Zone

Cental locking works well on 3 doors and tailgate but not on rear right hand door(88 touring).This door can either be locked / unlocked on the button but button will remain in that position.
Is this going to be the solenoid in that one door or could it be something else?
Thanks Steve

I'd check the central locking motor on that door 1st
Try replacing it with a good(known to work one)from one of the other doors and see if that makes a difference.
If it then works,a replacement would be in order

Thanks Dave. Sorted.
Replaced solenoid/motor.(wish I had smaller hands!!!!)
Perfectly working system
Hope it stays that way!