Central Locking problems

[mushdy]

Been having terrible trouble with my central locking recently  . It's been intermittent for a couple of weeks but there's been all sorts of crazy things happening with it the last couple of days. At the moment the only door which locks either with the fob or the global lock switch is the driver door. Now and again the passenger will give a little wibble in sympathy but won't lock fully. Also the driver's rear will no longer lock manually from the inside and appears to have resistance on the internal handle when I do try and push it to lock, although it opens fine from the outside. I have checked continuity with a multimeter on every wire in all four doors by removing the connector from the A and B pillars and using a sharp probe on the wire just where it exits the door frame to the pins on the connector - all seem okay (no visible breaks or signs of damage either). Earlier this evening I was trying the global lock switch a few times and all the internal lights stayed on and wouldn't turn off, even when the driver's door was locked and immobiliser armed!! Had to disconnect the battery for a few minutes and re-connect which has cured the lighting problem but the central locking is still the same - just locking the driver door. I'm at my wits end now - any suggestions very welcome! 
Chris

[gregers]

you missed 1 door,the rear hatch  the wires in the rubber boot are a known problem so check these.

[mushdy]

Hi Gregers...so do wiring problems under these grommets cause problems with the door locks, cos the tailgate is working okay...?

[Mirez]

Ha, I've just this minute come in from repairing a wire in my tailgate

Continuity isn't the issue here, its a short between the wiring caused by a breakdown in the insulation and its not always visible btw). They can be damaged in about 4 places under the grommet so you need to push 90% of it into the door. The only 100% check it to remove the loom and continuity check each pin against all the others.

From my experience, the rear doors and tailgate are the prone ones - FYI, All the wiring runs in the right hand grommet of the tailgate.

[mushdy]

Ah righto, thanks Mirez. I'm thinking I'll start with the rear driver's side door then, as that's the one that's giving me issues with the internal manual lock too. Just wondering, if there is a short in the wiring in the rear driver door harness could this then affect other doors or is it more likely those other doors have wiring problems too?

[Mirez]

It certainly could, its all "computer" driven at the end of the day - rouge signals and shorts confuse the ECU into doing weird and wonderful things that effect the whole locking system

[mushdy]

Thanks Mirez. Solved the manual locking issue on the driver's door anyhow. Took the door lock out and removed the white plastic housing that contains the motors and gears. Basically it looked like the motor had stopped mid flow and not returned to it's home position which meant it was not allowing the lock slider to be moved manually. A couple of spins on the motor with a watchmakers screwdriver got it back to its central position. After re-assembly and refit at least I can now lock all the doors from the inside manually. While the door card was off I probed all the door lock terminals to main B-post connector pins checking for continuity and shorts and didn't find any problems. Did the same on the passenger rear and no faults found. Time to check the front doors and tailgate now. Seems strange that the driver's door is the only one that works off the fob though......

[Chrispb]

I would always start by looking at the drivers door as this is opened and closed the most and is linked to all the other doors then the tailgate these are the most common.

See Here

[mushdy]

Cheers Chris, driver's door definitely next on the list 

[mushdy]

Gutted......completely removed the driver door harness and had a good feeling when I found the insulation on the large brown ground to be split. Repaired this and one of the speaker twisted pairs and 100% checked every wire for continuity and shorts (didn't find any problems). Re-fitted and it's exactly the same  . I guess it's to the passenger door next and then tailgate. Starting to suspect the module now though.......

[mushdy]

Well, I've now had all 4 door harnesses on the bench and checked for continuity and shorts. Did find the large brown earth was also split in the passenger door harness and there was some white residue on adjacent leads including the yellow and yellow/black (which I think are links between all 4 doors) may have been evidence of shorting? Repaired the large brown and re-tested & refitted but fault is still there. Really thought I might have sussed it this time! I also removed the tailgate grommet for a quick look but these wires look fine and the tailgate lock is working properly. Have been researching where the controller is located and turns out that it's part of the main bcm behing the passenger compartment fusebox. Might invest in a vcds lite cable and see if that flags up anything.....

[mushdy]

Fixed!!!  After having stripped out, checked/repaired all 4 door harnesses yesterday, the problem still existed. Feeling rather disappointed I left the galaxy at home this morning and got a lift to work only to find that when I got home the central locking was fully functional!! - all 4 doors, tailgate and fuel flap lock working perfectly every time off the fob  I'm thinking that after completing all the repairs on the insulation the BCM just needed time to reset?? Whatever it was I'm a very happy chap 

[Mirez]

Fantastic news, they can be a little "fussy" the old BCM so it could well be that after months of confusion it needed a little time - still great work

[mushdy]

Cheers Mirez, thought I'd have to put up with a future of reaching around and manually locking all the doors!! (bit of a pain with 4 kids!) Phew! 

[Chrispb]

Well done for persevering, incidentally in my how to repair the door wiring the only problem  caused by the broken brown wire in the photo was the drivers door window would not go down.

[mushdy]

Hi Chris, it seems from my experience in this that the large brown earth cable is the one which is most prone to suffering from cracked insulation, however the feature which is affected e.g. windows, central locking etc depends on which cable is laying adjacent the the large brown within the grommet. In my case the cables laying alongside it within the pass door grommet were the yellow and yellow/black which I believe control passenger and both rear door locks. Both showed signs of white residue which I now think was evidence of shorting. If your window control wires happen to be lying adjacent to the brown earth then it's gonna be window functions that'll be affected.