Technical Door lock

[tessiedog]

CLASSIFICATION: OFFICIAL


Hi folks

Looking for some help with a problem with the driver’s side door lock (1.4 16v 2004, 3dr). Background is that recently the remote function on the key stopped working and from looking at other posts on here about this, looks like the ECU will need reprogrammed using the right software to again recognise the key?, so might chase this up when I get the chance and see if there are any independents locally who might be able to do (opinion seems to be that this would be an expensive job at the Fiat dealer).

However, in the meantime, the key still works in the lock……but the problem is, only to lock and not to unlock – in the sense that it moves freely in the lock and will lock the car (anti clockwise turn) on the central locking (including the boot) no problem, but when it comes to unlocking (clockwise turn) even when the key is turned clockwise as far as it will go with a considerable (and probably not desirable) amount of force it will not unlock. Not really sure how the lock set up works, and so would be grateful for any knowledge that anyone could share. For what it’s worth the boot lock has long since given up working off the key, which might have been a last resort option to get into the car if the driver’s door lock failed to co-operate. At the moment, I’m not locking the car, which in my circumstances isn’t a major issue, thankfully, but would like to get something sorted.

Cheers

 

[jim cooper]

Did you change the battery in the key fob?

 

[tessiedog]

Hi Jim
First thing I did..... when it failed i was in Asdas car park so went straight in and bought a new one but still the same and anyway the key still starts the car. A local guy here tested the key and says it's ok (power, frequency etc?) but unfortunately couldn't do the relearn thing. So first priority is to get the car to lock off the key, hence the post on here.
Cheers.

 

[Ralf S.]

The back of the lock barrel (which is metal) transfers the rotating movement of the lock to the central locking motor via a white plastic rod.

The rod is connected to the barrel via a black plastic sleeve. The barrel is a push-fit into the sleeve (and is held in place by a couple of lugs on the barrel that engage into slots in the sleeve). At the bottom, the barrel has a couple more lugs that align with moulded recesses (or holes) in the sleeve.

When you turn the key, the rotating force is transferred through the sleeve by these bottom lugs, which are metal.. which in turn rotate the sleeve (against the resistance of the locking mechanism) and pull the white rod, which activates the lock.

Over time, the metal lugs on the barrel can fret the plastic sleeve holes/recesses... since the sleeve is made from softish (oil can type of ) plastic and can't handle it forever. Turning the key all the way over is essentially not exerting enough pressure on the arm (since the lock is turning in the sleeve rather than the sleeve transferring the motion to the arm.

You might be able to order a new sleeve but replacing the barrel is a proper Mo-Fo requiring the sleeve to be disconnected from the white rod (ball joint) after you have removed the internal door trim, support frame (you will receive at least 50 nasty cuts) and then still not be able to quite get your hands up inside the top of the door where the barrel/rod arrangement live.

The barrel (you'll want to keep yours, so that you can continue to use your existing key) can be detached from the sleeve but it's only "easy" if you rebuild watches for a hobby.

Before you go that route, also clean/check the actuator on the central locking since if that's dirty or lazy it won't "click" even if the sleeve is new (ask how I know) and the barrel and rod are all fine. In fact... given the absolute bitch-fight changing the lock is, I'd check the locking mechanism first.

Ralf S.