Central locking fault - Seat Ibiza

[Cylinder 8]

I've been reading PistonHeads for a long time and have finally decided to sign up as I need some help, so firstly: hello! Secondly, my first car is a 2007 Seat Ibiza 1.4, I've had it since July and I love it. However:

It has two faults with the passenger door. The first of which is the door switch doesn't work, meaning the interior light doesn't come on when the passenger door is open and if I unlock the car and get in the passenger side, I get locked in after 30 seconds because the car doesn't know the door has been opened.

The second fault is with the locking itself. When locked with the button on the key, so all the door handles are locked, it works fine. When locked with the button inside the driver's door, so only the exterior handles are locked, the passenger door doesn't lock at all.

I took it to a local garage the other day and they dismantled the passenger door and suggested the locking mechanism was at fault. I can't afford to spend £130 on a new one so I ordered a brand new but non-genuine part from Ebay, £40. My Haynes manual states that the door switch is built into the locking mechanism, so replacing it should have fixed both problems. I installed the new part today and the door switch now works perfectly: interior light and central locking both know when the door is open. The problem is that the locking still doesn't work properly, with almost exactly the same symptoms as before: not locking when locked from the inside. I have no reason to believe the new mechanism is faulty, so where does that leave me?

All I can think to do is buy a diagnostic fault reader and see if comes up with any codes. Is this worth doing? Any other help gratefully received!

[Who me ?]

In the absence of any replies, you could post this on Briskoda.net. Firstly, it's got Skoda bits, but it's also got places for other related makes, and Seat comes under the VAG banner, so there'll be someone who cam help. Lots of VAG Mastertechs on there. There's also a lot of blokes with VAG COM registered as wiling to help out, or if you want to get your own, there'll be advice on whre to go and what the codes mean.

[Cylinder 8]

Thank you, I'll post it in the "General Car Chat" section on Briskoda and see what happens. I'll keep coming back here to check this thread as well.

Cheers!

[Cylinder 8]

I've had a suggestion on Briskoda of a faulty earth. The wiring diagram shows the door locks are wired to an earth point in front of the gear stick underneath the dashboard, so I spent a while today dismantling bits of the interior to get to it. Why is everything in such a stupid inaccessible place?

[Cylinder 8]

I dismantled the door again this morning and checked the earth wire from the lock mechanism through to the earth point, all is well. That points towards an ECU fault, however I now think the new mechanism is faulty as I closed the door, locked the car, unlocked the car and found that the passenger door won't unlock. AARRRGGHHHH!

I've just realised there's a lever in the mechanism that has to be hooked up to a spring before the mechanism is refitted to the door. Guess which muppet didn't hook up the spring before putting it back together this morning!

So now I have to find a way of breaking into my own car!

Edited by Cylinder 8 on Friday 31st October 13:02

[Sheepshanks]

Cylinder 8 said:

The second fault is with the locking itself. When locked with the button on the key, so all the door handles are locked, it works fine. When locked with the button inside the driver's door, so only the exterior handles are locked, the passenger door doesn't lock at all.

Can I just clarify if you mean the passenger door can still be opened from the outside once the interior lock button is operated? You've sat in the car, pressed the button to lock it, and then had someone try and open the door from the outside?

Our Ibiza has been gone for a couple of years now, but I'm pretty sure you could still open the door from the inside if it was locked using the interior button (or the auto locking).

[Cylinder 8]

Sheepshanks said:

Can I just clarify if you mean the passenger door can still be opened from the outside once the interior lock button is operated? You've sat in the car, pressed the button to lock it, and then had someone try and open the door from the outside?

Our Ibiza has been gone for a couple of years now, but I'm pretty sure you could still open the door from the inside if it was locked using the interior button (or the auto locking).

Yes that's right. The inside handle should still work. The problem I have is that both inside and outside handles still work as though the car is unlocked.

[bigjobbo]

Have you checked the wiring between the door and A pillar for breakage inside the rubber grommet?

[Cylinder 8]

bigjobbo said:

Have you checked the wiring between the door and A pillar for breakage inside the rubber grommet?

Yes, it all looks fine. I also grabbed hold of the wires and moved them around while testing the continuity of the earth wire and everything seemed fine.

On Friday evening the door decided to unlock, meaning I didn't have to break in. I spent a while swapping the plug from the old mechanism to the new one and back again and seeing what happened. The old mechanism worked perfectly (it always was an intermittent fault) but the new mechanism wouldn't lock properly (again). It's as though the new mechanism is faulty in the same way as the old one, albeit permanently rather than intermittently. That would be one hell of a coincidence but I can't see any other answer, if it was an ECU fault, then both mechanisms should do exactly the same thing.

I've cleaned up the old mechanism and refitted it, I'll leave it for a few days and see if the fault comes back. This is doing my head in!