Door lock switch?

[graynada]

Sometimes on unlocking my drivers door the central locking doesn't unlock, just the drivers door unlocks, and of course if I open the drivers like this the alarm goes off. Unlocking the car via the boot always (touch wood) works.

I am guessing there is a switch on the lock barrel that controls this and it is this or it's wiring that is playing up.

Has anyone any advice/experiences to share?