Central Locking on the Fritz

[fuus]

Hi all,

Looking for some assistance in fixing the central locking on my 1.9 TDI Octavia.

The Problem: Passenger front door doesn't lock or unlock when pressing the keys, all 4 other locks lock and unlock as they should. All other components of the passenger door such as window, speakers, puddle light etc all function correctly. When the passenger door opens the courtesy / cabin lights above the gearstick do not come on.

Using a multimeter I've ruled out all the connections between the footwell and control unit inside the door. Where is next to check? I've been trying to find 12V on the two pins that control the lock inside the footwell but either they're dead or my multimeter is on the fritz.

 

Using a multimeter I've worked out there is continuity between passenger footwell and connections in the door, however I'm unsure where the next step closer to the CCU is best to check?

 

F37 (fuse 37?) which should be 30A according to the Haynes has a unblown 5A in it's slot? More confusion.

 

Any ideas folks?

 

Cheers

[mikec]

Possible pin problem on the window motor connection in that door?

[fuus]

The pins all look perfect to me, no corrosion at all may give it a lick of WD40 just in case Any idea what voltages are supposed to be present when the locks are activated at the footwell connector?

[YellowCar]

Soak the mech in lube, could just be ultra sticky if you're lucky. Check wiring loom too. Did you check pins in drivers door?

[fuus]

So both Lock pins in the footwell read 12V.

 

Brainwave: Door light doesn't come up on dash when you open the door so maybe it isn't getting that signal and thus isn't activating the lock? The puddle light is working so microswitch in the lock module is working but perhaps the connection between the microswitch and dash is dead.

EDIT: I can't work out where on the wiring diagram this points to, but I'm sure I'm on to something

[YellowCar]

Microswitch may well be a separate issue, when mine was playing up in drivers door it only failed to switch lights on and sound the buzzer sometimes, and not always the same lights. Replacing the drivers lock mech solved my microswitch issue, but didn't help my passenger door not dropping the button when locking, lube solved that. No harm in exploring what you've done, but you may be over thinking the issue.

Edited 23 March, 2016 by YellowCar

[fuus]

Well I've already replaced the microswitch in the passenger door so it can't be that. I've given it a good dowsing of lube and that hasn't made a difference.

 

Checking with a multimeter when the buttons are pressed both lock feeds have 12V all the time at the passenger footwell. At the motor there is no voltage at all to either motor pins.

[Outofthi5world]

Got pretty much the same problem in my track car, but with the drivers door thing is I've replaced the whole door minus the wiring look. I'll have to check that but otherwise it's an issue inside the car somewhere.

[YellowCar]

Check the loom for weaknesses and breakages particularly through door pillars and near window regulators

[fuus]

which pin from the window motor feeds back to the car whether the door is closed or not?

[FUBAR]

Soak the mech in lube, could just be ultra sticky if you're lucky. Check wiring loom too. Did you check pins in drivers door?

+1 The stem of many a random central locking issue, worth a look at pins in that one :(

 

 

This was causing me a lot of issues inc rear passenger door not locking/unlocking with the rest (that doors connector was clean and dry), that is solved, but the drivers door itself remains out of the loop unless I just use the key in it which I tend to do anyway so not a big drama. 

 

Edited 24 March, 2016 by FUBAR

[fuus]

Ah thanks FUBAR. I missed that. I'll have to get the drivers door apart next week.

[PaulOH]

My central locking has completely failed and the last time the computer was read, it came up with fault codes in all four doors. This points strongly to door ribbon connectors. Am hoping to replace all of them - including the boot lid - and we´ll see what happens.

 

Interestingly the door barrels on both sides of the car have now failed too so there´s no locking the car at all these days - apart from an occasional and spontaneous activation of one or more of the door lock motors... Thank the Lord no one would steal it in a fit!

[FUBAR]

My central locking has completely failed and the last time the computer was read, it came up with fault codes in all four doors. This points strongly to door ribbon connectors. Am hoping to replace all of them - including the boot lid - and we´ll see what happens.

 

Interestingly the door barrels on both sides of the car have now failed too so there´s no locking the car at all these days - apart from an occasional and spontaneous activation of one or more of the door lock motors... Thank the Lord no one would steal it in a fit!

 

My car has central locking but not remote central locking so the lock barrels are 15 years old and the drivers one was always stiffer than the others until the point it seized totally, no lube worked at all. I got a replacement barrel off ebay which fitted perfectly and works so smoothly it's made such a difference it came with 2 keys so I just added those one to each set I have for the car. If passenger one was to fail, I wouldn't bother replacing it in the same way as I don't want a big collection of keys and I don't get in that side etc, but other locks are still nice light and smooth! 

 

Not bad for under a tenner delivered tbh: I bought the same one but from a UK supplier for just under £15 as a matter of urgency, but they will all be the same ones.

http://www.ebay.co.uk/itm/170923219288

Edited 25 March, 2016 by FUBAR

[PaulOH]

Cool! That´s exactly what I was thinking of. Many thanks for the steer in the right direction!

[fuus]

Finally got around disassembling the drivers door, and not a spot of water ingress anywhere to be found...

 

so my problem in full detail:

 

Drivers door + diagonal passenger door both lock + unlock perfectly.

When plugged in passenger front door unlocks and locks as it should but also unlocks itself every 5 minutes or so, causing the battery to go flat. No sign of water in the door, I've checked every connection in the door and they all work.

Drivers side rear door, when locked locks at it should then immediately pings back up. If you continually press the lock button you can fight with it, but every time you lock it it pings back up!

Occasionally on long trips the drivers door unlocks itself once or twice (say once per 90 mins of driving).

Occasionally on long trips the trip computer flashes up with 'DOOR OPEN' (say once per 90 mins of driving) although not at the same times as drivers door unlocking itself.

 

 

Any ideas????

[YellowCar]

Think I'd be looking at the wiring loom and other plugs for weakness, fractures and breakages particularly where the loom passes door pillars and window regulators.

Not that I've explored it before but what about the CCM, the communications box in the dash somewhere? That's a guess though as I've never looked at it

Edited 23 July, 2016 by YellowCar

[fuus]

Right comrades! We have progress, I have disassembeled the door which always unlocks itself, I unplugged the loom from the door and measured the voltages to try and work out if the fault it upstream or downstream of that point:

 

The voltages I measured are as follows:

Red / Brown - 12V

Purple - 12V

Brown - earthed

Purple / White - 0.34V

Red / Yellow - 12V

Blue - 0V

Blue / Brown - 0V

 

Anyone got a wiring diagram they could send me? Or know what voltages should be present?

 

Cheers, Fuus

[fuus]

anyone??

[KenONeill]

Post a photo of the other half of the connector.

[alimac81]

Are you able to get a spare known working CCM? It would be worth ruling this out as it would save a lot of head scratching and pulling wires apart.  If there is no sign of water damage to any of the connectors then that's the next place I would look as previously suggested on this thread.  Might also be worth while cutting some lengths of wire to slave in from the CCM to the door connector to rule out wiring issues.  You could be getting a break down in the control signal l wires ( purple, purple/white wires), as it seems you are getting power to the door just intermittent trigger signals.  Did you measure the voltages while operating the door locks via the key fob?  

[fuus]

I have a Seat Leon Mk1 I'm breaking, are the CCM's compatible?

[alimac81]

Not sure if the CCM's are compatible, so but best to check.  See if you can access your CCM to confirm the part number, i'm not home at the moment otherwise id be able to find out for you.  

[fuus]

Will I be able to find it on Elsawin?

[alimac81]

possibly, but i personally would find it easier to just take the lower dashboard cover off under the steering wheel and have a look.  I found a link on google that may help. http://uk-mkivs.net/topic/18621-were-and-how-ccm-module/  do you have or have access to VAG COM? its needed to code your keys to the CCM.