Key locking confusion

[Adox]

The locking on my Mk2 estate is very peculiar.

 

I should say that the rear offside door doesn't lock or unlock at all as, according to the service history, it was 'disabled' for some reason. I have to use the emergency system outlined in the handbook.

 

That aside, the locking situation is as follows:

Locking with the key When I use the key in the driver's door to lock the car, the central locking works - all doors lock and the red alarm LED flashes. When I unlock with the key, only the driver's door unlocks. Everything else stays locked and the alarm is still active. Going by the scratches around the lock, this was the preferred method of the previous owner.

Locking remotely When I lock remotely with the key fob, all doors lock except the driver's door. Two beeps on the fob unlocks the doors that the remote locked. If I have locked the car with the key, two beeps unlocks everything except the driver's door.

 

As a result, I have to use the key to lock, and then two beeps AND the key to unlock without the alarm going off

 

Does this imply that there is some sort of wireless receiver fault in the driver's door lock? If so, do I need to replace the whole lock/actuator, or is the wireless receiver available as a separate unit?

 

I would be grateful for any help.

 

Thank you

Edited 23 November, 2022 by Adox

[Breezy_Pete]

The receiver for the key fob signal is central, in the central convenience control unit behind the dash, the locks are dumb electromechanical devices - just a motor and a few microswitches.

 

Does the car have electric windows?  If so, can you get them to go down by turning and holding the key turned clockwise in the door lock starting with a locked door?

 

 

 

 

[Breezy_Pete]

There's a thin green/yellow wire in the bundle that goes between door and A-pillar that conveys the lock's status to the central convenience unit; I wonder if that's broken?  Have you done any inspection of these wires?

[Adox]

Thanks for such a quick response, Breezy Pete.

 

Yes, the car does have electric windows. I'll try what you recommend once the rain stops (its chucking it down).

 

I'd be interested to know your thinking behind this manoeuvre. Shorting, cracked wire loom?

 

Thanks again 

 

Sorry, I replied before reading your second message.

[Adox]

I'll check the wiring loom (when its stopped raining). I presume its behind the massive flexible trunking near the hinges

 

[Breezy_Pete]

1 minute ago, Adox said:

I'd be interested to know your thinking behind this manoeuvre. Shorting, cracked wire loom?

The signal from the lock unit which says "key is turned" goes via the electric window motor module. What I've suggested is a way to establish if that signal is actually getting out of the lock module as far as the window motor module.  If it does cause the window to open, turn the key the other way and check that it also closes.

 

This isn't the same signal as I was referring to in my second post, that one goes directly to the central convenience module.

 

1 minute ago, Adox said:

I'll check the wiring loom (when its stopped raining). I presume its behind the massive flexible trunking near the hinges

 

Yep. Photograph any broken wires for identification purposes, please.  Very common fault on mk2 Fabia.

[Adox]

OK. So with a slight pause in the rain, I tried opening and closing the window with the key in the door lock. Worked like a dream.

 

So what does that point the problem towards?

 

(Too wet to expose the wiring yet)

[Breezy_Pete]

I think that rules out a problem with the lock module, and points towards the wire I mentioned above, the thin green/yellow one between a-pillar connector and door.

Goes to pin 3 of the a-pillar connector. This is how the numbering goes, looking at the mating face of the door loom plug:

 

 

 

[Adox]

I've got the boot off at the A pillar end and no obvious breaks in the wiring, although not exactly easy to get at the tangle of wires.

 

What's the trick to release the boot at the door end?

 

How do I release the plug at the A pillar end? It looks as if the orange clip should click down from vertical , but seems stiff and don't want to break it

[Adox]

Managed to get the boot a bit further back and found a broken wire, but it is purple with a yellow stripe and appears to go to pin 3 of the connector

[Breezy_Pete]

That'll be the one.  The wiring diagrams are sometimes confusing with wire colours on LHD vs RHD mirrored things like door looms.

Pin number says it's the right wire.

[Breezy_Pete]

Are you sure it isn't pin 2? 

Re-reading your symptoms, the wire that's not working is one of the motor power wires which is purple/yellow, and comes from/goes to pin 2 of the connector.

[Breezy_Pete]

There might be more than one bust wire, I guess.

Photos would help, if you can get that connector latch open for better view/access (be brave).

[Adox]

56 minutes ago, Breezy_Pete said:

Are you sure it isn't pin 2? 

Re-reading your symptoms, the wire that's not working is one of the motor power wires which is purple/yellow, and comes from/goes to pin 2 of the connector.

Yes, my mistake, it's pin 2

[Breezy_Pete]

I misread your initial post and thought the motor was working one way (but not the other). It uses the same two wires for each direction, just by swapping the polarity, so I thought they must be OK.

But re-reading, I see that the only time the driver's door is locking or unlocking is when the key is doing it directly, mechanically.

 

Not 100% sure but that may be the only broken wire, and things should work as intended once repaired. Fingers crossed.

 

[Adox]

52 minutes ago, Breezy_Pete said:

There might be more than one bust wire, I guess.

Photos would help, if you can get that connector latch open for better view/access (be brave).

Yes, I did force the orange clip back. Seemed to be lots of locking and locking as I did so, presumably the connector making a breaking contact as I wobbled it.

 

No other obvious breaks. The purple/yellow wire has broken right next to the cloth tape binding the loom so soldering in a repair in situ would be nearly impossible. Is the best plan to take off the door card and take the whole loom out to repair it?

 

Need the car in a minute, so have put everything back for now, but will take photos when I get back to it.

 

Thanks for all your help. I feel I'm on track now.

 

Then there is the 'disabled' rear door lock....

 

Oh, and the rear shelf locking clips ...

 

Oh, and the clutch thrust bearing/input shaft bearing that rattles sometimes on idle ....

[Breezy_Pete]

2 minutes ago, Adox said:

Is the best plan to take off the door card and take the whole loom out to repair it?

I've not had hands on/in situ experience of repair on a mk2, but on a mk1 it's surprisingly easy to take the whole door off, improving access enormously.

 

I think from what I've read, you can get the loom out via door car off, plus removing the loudspeaker?

 

Others with hands-on experience will be able to better advise.

[Breezy_Pete]

Skoda Workshop Manuals > Fabia Mk2 > Body > Body Work > Front door, central locking > Front door > Removing and installing the door (workshop-manuals.com)

 

If you try this, make sure you have an assistant available, doors are heavy, and aligning during refitting is much easier if someone else has the weight.

Edited 24 November, 2022 by Breezy_Pete

[Adox]

Break in the weather and I managed to solder in a length of wire in situ, so didn't have to strip the door trim or take the door off. Will do for now.

Best bit is that it has fixed the front door problem. Now all (except the 'disabled' rear door) lock and unlock with the fob.

 

Again, thanks for your help

 

PS. Can you think of any reason the previous owner's garage disabled the rear door lock? Shorting and blowing fuses?

[Breezy_Pete]

Dunno about the rear lock, maybe just another broken wire going to that door?

[Adox]

Well I got the rear door stripped and found that the lock had been intentionally disabled - by unplugging it. I plugged it back in and tried it, expecting a fuse to blow or something, but it seems fine. So now I have full remote central locking, for the time being at least.

 

Also got the boot linings off and replaced the clips for the cover, so now that works as it should.

 

If only I could get rid of the occasional rattle on idle, the car would be perfect.

[Me-109]

Did the door panel rivets look original? Electric rear windows? I wonder if someone has been in to change the window regulator. The lock is probably the last thing you would be connecting. They are a pain to get off and maybe the spring clip is broken, so might have come adrift if it had been reconnected. 

[Adox]

On 04/12/2022 at 09:26, Me-109 said:

Did the door panel rivets look original? Electric rear windows? I wonder if someone has been in to change the window regulator. The lock is probably the last thing you would be connecting. They are a pain to get off and maybe the spring clip is broken, so might have come adrift if it had been reconnected. 

No electric windows in the back and a note in the service history that a garage had charged to 'Disable rear door lock'. It seems that they unplugged it for some reason.

[nikasp]

On 26/11/2022 at 16:13, Adox said:

Break in the weather and I managed to solder in a length of wire in situ, so didn't have to strip the door trim or take the door off. Will do for now.

Best bit is that it has fixed the front door problem. Now all (except the 'disabled' rear door) lock and unlock with the fob.

 

Again, thanks for your help

 

PS. Can you think of any reason the previous owner's garage disabled the rear door lock? Shorting and blowing fuses?

Did you manage to see the break easily or had to open the wiring loom? Currently down with a bad cold but will check tomorrow, think I also have a break somewhere that causes the driver door (only) to not lock via the remote. Unlock works. 

[Adox]

17 hours ago, nikasp said:

Did you manage to see the break easily or had to open the wiring loom? Currently down with a bad cold but will check tomorrow, think I also have a break somewhere that causes the driver door (only) to not lock via the remote. Unlock works. 

I had to undo the tape binding the loom because the break was exactly on the edge of the tape. After soldering in a repair wire, I taped it all up again. Quite tricky because there isn't much room to work, there's little or no spare length on the loom and the wiring has that horrible hard insulation. Had to use a Stanley knife to remove the insulation instead of wire strippers.

 

Good luck. It's worth the effort just to have everything working properly