Right, what would cause a VW Passat's door lock to stop working?

[northwind]

This is a bit odd... Just doing some work on my dad's old passat (a B5 model 1.8 20V estate) and the driver's side door jammed locked. I never touched it! Honest! The central locking's been iffy since it flooded last winter, he's never bothered to dry out the wiring properly and I'm not doing it because if I break it, it's all my fault. So...

Symptoms: when engine not running:

Inside door handle still unlocked the door
Central locking neither locks or unlocks the door
When you turn the key in the door from the outside to lock it, it doesn't lock- the lock button inside the door moves slightly but doesn't click down. It does trigger the central locking on the other doors (though erratically).
Pushing the lock button inside the car doesn't work- it physically won't move down.

When engine is running:

Inside handle still works
Central locking doesn't work at all (possibly intentional)
Door locks and unlocks as normal from outside
Lock button inside car still doesn't work.

I don't know how much of the lock workings of a semi-modern car are electrical, and how much are mechanical... The car had a flat battery when I started, so I'm thinking that perhaps there's an electrical part, wee stepper motor or piston or something, that's not got enough power to drive it. That'd tie in with the fact that it works differently with the car running, since it's charging normally (I think) but was only about 11.5V across the terminals when I last checked it.

Oh yeah... Anyone know the correct charging voltage for a passat? It's 14.1V at idle just now. The car was driven a fair distance just 2 days ago so I don't know why the battery's flat, but it's been very wet so maybe the knackered electrics just struck again.

(I don't know much about cars, but there's a big generator-looking thing bolted to the front of the engine, which is driven by a belt run from the same spindle arrangement that runs the fan motor- presumably spun off the crank. So, presumably if that belt's slipping, the car wouldn't charge right?)

I think it's fubarred. hth

[northwind]

Nah, not at all- I've left an old guitar strap in the passenger seat which he can use to strap the door closed if it breaks again, good as new! I think that should add value, "Custom Levys door locking mechanism, very rare on UK spec cars" dAnd nobody's likely to steal it

[skeetly]

Classic passat leccy problem.
My '981.8t has done strange things forever.
I love it though so I put up with it all
The door locks are notorious; they have little electronic microswitches that play up.
Trying to get some contact cleaner in there can help but its awkward.
The switches are part of the lock so you have to change the whole expensive lock.
Check these forums out for lots of info and sympathy:
http://www.passatworld.com/forums/

Not sure.

But it happened to 3 out of the 4 doors on my dad's passat tdi estate.

He went and took off the panels behind the door and fixed it somehow. Unhelpful I know, but he didn't have to buy any replacement parts, that much I know. I'll try and find out.

[skeetly]

If you decide to swap the locks:
http://www.taligentx.com/passat/main...lockmechanism/

Solenoid.

[northwind]

Ah, brilliant, thanks for those- off I go to passat.org

[punyXpress]

My VW group ( Skoda ) played up.
Lock the door - either key or remote & within 10 minutes:
Clunk Click Whirr
Doors unlocked & windows wound down.
Culprit was electrical connector in passenger door opening.
Squirt with WD40, keep car for a couple of hours, that'll be lots of pounds, sir. An expensive way of extending the learning curve!!