Driver's Door Lock Replacement
137,000 miles, 19th June 2012
Background
About 3 months ago I occasionally heard a buzzing noise when using the key fob to lock the car. It appeared to be coming from the driver’s door. The door still locked and the indicators flashed to confirm the alarm had been set but I kind of knew that the driver’s door lock was probably on its way out. I did a little research and saw that other people had experienced the same problem. A scan using VCDS confirmed the problem:
"Address 42: Door Elect, Driver
1 Fault Found:
01552 - Motor for Central Locking; Drivers Door (V56); Lock
012 - Electrical Fault in Circuit - Intermittent"
Over the next few weeks the problem got progressively worse. Sometimes the door would not lock on the first attempt. A second attempt would usually fix it. Then it got to the stage where the door would never lock. The indicators wouldn't flash since the car could sense that the door hadn't locked. Also the interior door lock control didn't light up when you pressed lock. Again, probably because the car could sense that not all the doors had been locked. I had to start using the key to lock the driver’s door. As soon as I did this, the indicators flashed to confirm that the alarm had been set.
During all this time, I could still unlock all the doors using the key fob.
The fix
After a little research on the internet, reading my Haynes manual and talking to the guys at my local VW dealership, I found out what was involved in replacing the door lock module myself. A new driver’s door lock module (part number 3D2 837 016 S) from the VW dealer cost about £120 all inc.
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Replacing the module was fairly easy but gaining access involved removing the outer door skin. This sounds like a big and complicated job but actually the Mk V was designed so that this could simply be unbolted. The only complicated thing was before you can remove the door skin you have to remove the door lock barrel and door handle. Again, these are not terribly complicated but you have to take your time and follow the instructions carefully to ensure you don’t run into problems.
I followed the instructions in my Haynes manual which I found very good but I also found this great article online. It essentially describes the same method but has lots more photos and it was good to have a second perspective.
I can’t really add much to that guide except to say something caught me out. The door lock module is held securely in place with two bolts. I had assumed these would be torx head bolts but no. With the door skin, door lock barrel and exterior door handle removed, I discovered I needed an M6 spline in order to remove them. The guide does say this quite clearly but I hadn't noticed. Consequently, I had to temporarily re-attach the door skin and drive to my nearest Halfords store. I'm now the proud owner of a very nice 7-piece spline bit socket set. Cost £24.
Test of improvised tool to "set" the
door lock module prior to refitting.
Click on photo to enlarge.
One thing the online guide does not mention is the need to fix or “set” the door lock module after it and the door skin have been refitted, prior to refitting the exterior door handle. This is apparently to ensure that the handle is reconnected correctly. My Haynes manual tells me that whilst VW technicians will have their own special tool, it is quite easy to fabricate one yourself using a length of stout wire. I did this using an old wire coat hanger. See the photo (right) of my improvised tool being tested prior to the lock module and door skin being refitted. To be honest I'm not exactly clear what setting the module achieves.
So that’s it. The new driver’s door lock is working as good as new and hopefully it will last at least another 8 years.
This incident has made me grateful my car has the convenience door unlocking feature where the first press of the key fob only unlocks the driver’s door and you have to press it a second time to open the remaining doors. I figure, this might be why the driver’s door lock has failed first and may have extended the life of the other door lock modules.
Miscellaneous
Make sure you get the right replacement lock module. VAG Door Lock Module Part Numbers guide.
Before reattaching the door skin (for the second time) I noticed slight bubbling of rust under the paintwork on the very bottom edge. I guess you would expect to see early signs of rust here on an 8 year old car. It wasn't so bad but I cleaned it as best I could and applied a little rust-preventing paint. Hopefully this might delay the rust’s progression.