Door lock promlem- FIXED! (with pictures)

[shermand100]

2008 Audi A4 2.0 Tdi

Hi all, first post here. This forum has been an invaluable source of info for me with a couple of past problems, so I thought I'd share a solution to one i've been working on this weekend. I've seen a few other people have had this exact same problem, but haven't seen any solutions anywhere yet other than buying a new door lock. Hopefully this can help someone else and save them a bit of cash.

So the symptoms...

Rear passenger side door lock fails to open from the outside (when unlocked haha).
Door can be opened from the inside only.
Once door opened from inside, if door re-closed but not locked, it can then be opened from the outside.
Problem initially intermittent, eventually permanent.


So I'll assume the person reading this can remove the door lock for access and show the problem and fix. At the bottom of this post I'll have a general guide for removing door trims and the location of the bolts etc.


so with the lock unit removed, behind the grey pannel (screw part removed) you'll find the mechanism below...




At this point I would suggest plugging the lock mechanism back into the car, pressing the lock/unlock buttons on the fob and get familiar with what does what. To save a little time I think that...

The green bar is related to the child lock (irrelevant to this)

The piece of metal at the top of the pic with the "S" stamped into it, pivoting on the pin is the connection to the outside door handle, via cable you disconnected to remove it from the door.

The internal door lever operates via the same style of attachment as the exterior but is mounted on the reverse of the lock and not shown in any pictures.

THE PROBLEM At the bottom of the photo are two micro switches, operated by two sprung pieces of metal, which in turn are depressed by rotating plastic hammers (both shown). One hammer is orange in colour (in down position for operating the left micro switch), the other light grey in colour for operating the right-hand micro switch (currently in up position, switch depressed)

The problem is that both hammers should be up and switches depressed for locked
or both hammers in lower position, switches released for unlocked

The right-hand grey hammer, due to wear is able to "over rotate" and gets stuck in the up position making the door un-openable from the outside. To solve this...



I have screwed a buffer/stop so as to prevent the hammer over-rotating past a point it is able to return from. To do this i heated a needle on the stove and melted a pilot hole where to stop was going to be, and then drilled a 1mm hole into the black bar behind the "hammers". Into this hole i inserted a small screw. My backup plan was to use part of the drill bit snapped off at the base (as it's a hardened metal). I then protected the hammer by coating it in a sleeve of black rubber tube so that it didn't get damaged by the repetitive contact with the new stop. A drop of glue was added so the rubber tube/sleeve doesn't slip once installed.

I understand this fix won't be to everyone's liking, but is a good understanding of the problem and besides replacement and high cost was how i went about solving it. I'm sure there are other methods of preventing the "hammers" from over-rotating, but this is the method i went for with the materials i had. It works fine now and will certainly post if the component fails.

I will post below how to remove the door trim shortly.

Again I hope this can help someone sort out the same problem which appears to be a common one.

Regards
Dan

[thescouselander]

I had the same problem but I diagnosed it as a poor connection with the actuator motor contacts - I posted the fix on here some time back.

[shermand100]

Hi, when i posted this it seemed to be a common problem with few solutions. Now since I've had a look through your past posts history I've noticed a few. Thanks for making yourself known as my search of the forum hadn't bought up your posts. Anyway I liked your fix too and there was another here I'm sure you've seen
Door not opening from outside door handle after unlocking the car with the remote.

It seems odd that if that this can be fixed through a mechanical method (in my original post) and electrically from your method and the one mentioned above.
I would like to try the one in the post above as mine has failed again and there seem to be enough images to enable me to work out how to get to the electronics for a thorough clean/trouble shoot there.

Failing that, my next option is to buy a new unit, and they do look like they can be sourced directly from the factory in china at a substantial cost saving
OE3C4 839 015A REAR LEFT CENTRAL DOOR LOCK LATCH ACTUATOR MECHANISM FIT FOR VW PASSAT B6 SKODA SUPERB A4 A5 Q5 Q7 TT 8 PINS-in Alarm Systems & Security from Automobiles & Motorcycles on Aliexpress.com | Alibaba Group

just seems annoying that there are so many people having issues with this with no permanent solution besides replacement.

Hows yours now?
Dan

[thescouselander]

Hi, when i posted this it seemed to be a common problem with few solutions. Now since I've had a look through your past posts history I've noticed a few. Thanks for making yourself known as my search of the forum hadn't bought up your posts. Anyway I liked your fix too and there was another here I'm sure you've seen
Door not opening from outside door handle after unlocking the car with the remote.

It seems odd that if that this can be fixed through a mechanical method (in my original post) and electrically from your method and the one mentioned above.
I would like to try the one in the post above as mine has failed again and there seem to be enough images to enable me to work out how to get to the electronics for a thorough clean/trouble shoot there.

Failing that, my next option is to buy a new unit, and they do look like they can be sourced directly from the factory in china at a substantial cost saving
OE3C4 839 015A REAR LEFT CENTRAL DOOR LOCK LATCH ACTUATOR MECHANISM FIT FOR VW PASSAT B6 SKODA SUPERB A4 A5 Q5 Q7 TT 8 PINS-in Alarm Systems & Security from Automobiles & Motorcycles on Aliexpress.com | Alibaba Group

just seems annoying that there are so many people having issues with this with no permanent solution besides replacement.

Hows yours now?
Dan

I havent got my A4 any more but as it happens I have an original VAG door actuator for the near side rear in my garage. Basically I bought it but never fitted it as I got the old one working so I'm looking to get rid of it at a reasonable price.

[Alex jb]

I had this problem over the last few weeks too.
I didn't have wear in the parts so took apart the section with the motors and it seems to have been the contact issue.



I took the motor out, tweaked the contacts a little rotated the gear about 120degrees to make sure the windings were stopping/starting in a different position than before, then put it back together...
All is well for now.
Wondering if you can buy this motor from Maplins or RS?



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