Possible Door Lock Microswitch Fault Repair

wilco184

Member of the year 2015
Hello,

I have recently had the problem of my rear left door causing the locks to cycle when I put the key in the ignition. It was intermittent, although it happened seemingly more with a colder ambient temperature. VCDS confirmed which door was causing the issues, with the fault of 'wont de-safe' or 'can't unlock' or similar, I forget the exact words used. The locks cycling became extremely annoying, very quickly. I've seen this fault recorded on the forum before, but no documented fix for the A2.

As AJSelllors has said in another thread, problems with door microswitches on Volkswagen/Audi group cars of the same era are certainly common. I read posts mostly affecting the MKIV Golf over at TDI Club. There was an excellent post on here by Spike showing a repair video for a MKIV Golf, which I used a lot when repairing my own module. The link is here. http://www.youtube.com/watch?v=z5dtdyDDgrw

Once I knew what the common faults with these modules are, and how to remove it, I went ahead and attempted a repair.

I'll spare the details of removal, as it has been covered thoroughly by 'the grim reeper' before. I add my thanks for this, the instructions are great. I will add that I also didn't have to remove the window mechanism, the module can fit around it. The link to the instructions are here. http://www.a2oc.net/forum/showthread.php?13246-How-to-replace-rear-door-micro-switch

Once the module is removed, it looks like this. I apologise for the poor quality photographs, they were taken with my iPhone 5 under artificial light. Something I feel the iPhone lacks ability with.





The video I've linked above shows how to disassemble the module. The A2s lock is very similar to the Golfs, and screws you need to remove are in the same places. The smaller of the two types is a T10 Torx, and the larger is T20 if I recall correctly. Once the module is split into its two halves, it looks like this.



As stated in the video, the module is effectively two halves. One mechanical and one electrical. In the above picture, the electrical half is on the left hand side. With the T10 screws removed, and the red plastic piece facing down, the casing pulls apart easily. I would add not to remove the T20 screw keeping the red plastic part on, I did, and it was unnecessary and took a while to put the two springs back on. Inside, you will be able to see the main blue circuit board, two motors and various linkages.

Next, you can pull up the circuit board from the casing. It lifts fairly easily, and detaches with the two motors and connector. When removed, it looks like this.



As you can see in the photograph above, my module has appeared to have kept very clean inside. There was no evidence inside the case of any ingress, and the microswitches looked as new, with the rubber seals on the plunger also looking healthy. I checked the operation of the switches with a multimeter using the resistance measurement function. A range of 200 Ohms will be fine for this. You will need to trace the tracks from the switches back to the connector pin solder terminals and measure from there. My switches operated correctly, with a measured resistance of just less than 1 Ohm. I assumed this to be normal. Under closer inspection of the terminals however, one terminal in particular looked a bit 'suspect', if you know what I mean. I can't be entirely sure, but I strongly suspect a dry and cracked solder joint was the cause, in my case. I would recommend checking this. I reflowed all of the joints on the board for good measure, and then confirmed the continuity of the switches once more.

Reassembly can then begin. It's pretty much the reverse of taking it apart. Make sure not to over tighten the screws as the soft plastic threads can easily strip. The module can then be installed back in the car. Remember to replace the thin foam cover over the module; I forgot to and left it inside the door, I'm still annoyed about forgetting this. Plug the module in and test. I wouldn't replace the aluminium inner card without testing as I put a linkage back incorrectly first time and the door wouldn't lock, although I'm sure this would be difficult to replicate how I misplaced the linkage.

Reassemble the rest of the door and your done! :)

It's good not the have the annoying lock cycle and convenience module fault anymore. In fact, with my Q to AF CCCU conversion done recently too, I'm very happy not to have any CCCU related faults stored. Good times. :p

I hope this is of some use. If you're confident with stripping the door down, I'd say it's certainly worth trying. Especially seeing as the module costs a considerable amount.

Regards,

Matt.
 
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DJ 190

A2OC Donor
Yes, exactly the same problem I have suffered with! I have (just) had my CCU replaced [although with a "Q" type] and I haven't had that problem for a while, anyway. At least I'm ready for a cause and how

to rectify it, thanks to your excellent thread! Thanks for that!

David
 

wilco184

Member of the year 2015
Yes, exactly the same problem I have suffered with! I have (just) had my CCU replaced [although with a "Q" type] and I haven't had that problem for a while, anyway. At least I'm ready for a cause and how

to rectify it, thanks to your excellent thread! Thanks for that!

David
Thanks for your kind words, David. :)

I must add, I can't guarantee this fix will be the same for everyone as this is the only lock I've repaired, although with a repair cost of nothing, it's certainly worth trying!

Regards,

Matt.
 

ajsellors

A2OC Donor
Thanks for your kind words, David. :)

I must add, I can't guarantee this fix will be the same for everyone as this is the only lock I've repaired, although with a repair cost of nothing, it's certainly worth trying!

Regards,

Matt.
Hi,

the most common problem with the internal switches seems to be the solder joints although the switches do occasionally fail mechanically. On the A6 lock I have apart on my bench at the moment, the locked and unlocked switches are intact but the switch mechanism feels "worn" when compared to the two switches activated when the key is turned. I have read of people swapping the "key" and "lock/unlock" switches round but if the switches are unreliable due to wear I would not want the "key" switch to fail to work when the remote buttons get unpaired!

Given the amount of hassle involved in getting at the locks on the A2 I will replace the internal switches as well as re-soldering the joints. They aren't expensive once you can get hold of them.

The more illusive switch is the external one which provides the "door open" signal. I have found this and ordered some:

http://www.aliexpress.com/item/VW-Polo-Octavia-Sagitar-Bora-Golf-Passat-locks-block-the-micro-switch-door-light-switch/2024135625.html

It looks identical and is described as a part to repair VW door locks.

Delivery is at least free, if slow. I'll do a post with my experience once I have the parts.

regards

Andrew
 

wilco184

Member of the year 2015
Hi,

the most common problem with the internal switches seems to be the solder joints although the switches do occasionally fail mechanically. On the A6 lock I have apart on my bench at the moment, the locked and unlocked switches are intact but the switch mechanism feels "worn" when compared to the two switches activated when the key is turned. I have read of people swapping the "key" and "lock/unlock" switches round but if the switches are unreliable due to wear I would not want the "key" switch to fail to work when the remote buttons get unpaired!
Hi Andrew,

Thanks for the information, your research into this is certainly very helpful! :)

For modules where the microswitches have failed mechanically, have you managed to source the internal PCB mounted items? I had a quick look at the places I'd usually source components from before I disassembled my module, but could find nothing. I don't think they're for sale commonly. You have made a great find with the microswitch in the mechanical half, I'll be saving the webpage for that, just in case. :p

Many thanks,

Matt.
 

wilco184

Member of the year 2015
Two weeks later and the microswitch issue hasn't reoccurred at all. No more cycling locks with the ignition and no fault codes stored. :)

Re-soldering the joints on the PCB definitely seems to have fixed the issue. A happy outcome with effectively a free repair. Weirdly though, a few days after, a different door refused to unlock on one occasion, but has been fine ever since. Very strange.

Regards,

Matt. :p
 

PaulA2

Well-Known Member
Another successful repair completed by me and thanks for the heads up, it would appear that solder joints are weak in the rear locks. Chuffed as means I can repair for zero financial cost again!

Thanks very much for the useful guide, interestingly my locks had a coating on the PCB which had to be scratched off before hand. For good measure I re-did all joints.
 
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ukrainian

Member
So, as this thread was extremely helpful I thought I would just add to it rather than start a new one. My rear locks started cycling when ignition was turned on. Intermittently at first but recently it became every time. Also the DIS/interior light stopped reacting to the rear right door opening. VCDS scan returned this :
01561 - Left Rear Door
59-10 - Can't Unlock - Intermittent
01561 - Left Rear Door
61-10 - Won't De-Safe - Intermittent
01562 - - Rear Right Door
59-00 Can't Unlock
01562 - Rear Right Door
61-00 Won't De-Safe
So the rear right door card had to come off, then the Alu panel behind it with the speaker,. There was minor collateral damage to one of the plastic clip holders at the bottom of the door card (not the white clip itself). I got the lock mechanism out - found this a bit easier than when I got the lock out of the front passenger door previously. I took apart the lock just enough to get to the PCB and reflowed all the microswitch solder joints and the ones for the connector for good measure. Put it back together and all is well - the lock cycling is gone and VCDS fault codes for rear right door have disappeared. So far so good, it has been a week since. The 'intermittent' fault codes for the left rear door have come back but no obvious signs of a problem like lock cycling or DIS/interior light malfunction. Probably just a matter of time but I know what to do now.

So as suspected it was a continuity problem, most likely caused by a dry solder joint. The only other place where it could have been was oxidation in the cable harness connectors of which there were two betwen lock and main harness. But it didn't occur to me to rule that out as potential cause before I had the lock out and in bits.

Door reassembly did not go smoothly, I forgot to clip back in its correct position the steel lock release cable (this is the end near the lock and behind the Alu panel. This I believe prevented both exterior and interor handles from releasing the lock once I shut the door! So the door card and the Alu panel had to come off one more time, only now with the door shut :rolleyes:. Well it's certainly possible to do, and once the lock release cable was correctly clipped into place all was well again.

Once again hats off to all who have been through this experiemce before and shared it on this forum, the job was made so much easier for that.
 

ukrainian

Member
A couple of weeks ago I did it all again with the left rear door (minus the cockups this time:)). Reflowed all solder joints. Same outcome, the intermittent 01561 59-10 and 61-10 VCDS fault codes have not reappeared for two weeks now (used to come back within a day or two). No more central locking related faults codes, yay!
Discovered that the door card on this door had been off already - one of the clip locations was damaged (a bit of plastic broken off and missing), there was a random part left in the door that turned out to be completely unrelated to the A2, plus a load of swarf in the tweeter that was stuck to it magnetically. We've had the car since new and the only people who could have done that are the Audi dealership where it was serviced/repaired :rolleyes:
 

audifan

A2OC Donor
Just to explain a bit more about the two types of lock issues. first one is the lock cycling, wont desafe etc message. This is caused by the lock and lock microswitches inside the lock. These are usually fixed by the reflowing of the solder joints and cleaning of all connections. The second is the door open microswitch, this is the one that switches on the door symbol in DIS and the interior lights. On the drivers door also works the fuel flap release button. In this case you have to try to clean the accumulated grease and rubbish out from under the door latch mechanism. If this does not cure it then the switch will have to be replaced, it is external to the lock assembly on its rear face. Many get confused as to which microswitches are at fault so hopefully this will help others.
 

Vic

Member
Today strange noise started when rear door lock ulonck. Removed microswiched and some part are lose from their place.

Where this part should be installed (maybe photos?)?

20190915_132324.jpg
 
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