C locking borked - any ideas?

[Spion]

So, last night my central locking broke.

Symptoms:

Key difficult to turn. Not activating the electrics when turned. When turned full to left key stuck in lock, difficult to turn back to 'upright' position. Doors other than driver's will only open individually.

I think it's something to do with the locking system in the door, rather than the electrics on the CL system as a whole.

So, what can go wrong with the CL system in the vicinity of the actual lock?

[daimlerman]

Sounds like the lock barrel requires a bit of lubrication to me.
May be easier with the barrel out of the door,then you can stand it key slot up and let the oil soak into all the moving parts.
In the same area is the link to the c/l solinoid,but this is unlikely to jam.

[Touring Whore]

Don't use oil to lubricate a lock! Oil causes particles and debris to stick to the mechanism, causing more wear and tear. The only thing you should use is graphit powder IIRC.