E30 Zone

I cant get the deadlock to work on my e30, when I turn the key in the drivers door the doors lock but then nothing happens when the I turn the key to the deadlock position.

Any ideas much appreciated

Could just be a corroded pin in the door hinge post plug and socket, but this pin doesn't usually give trouble. Usual cause is slight wear in the operating arrangements for the microswitch worked by the lock barrel.
Cured by removing the lock barrel and the plate that the microswitch is mounted on, and putting a slight bend in the operating arm for the switch.
One of many little tweaks I do to all E30s that pass my way.