Door locking mechanism rebuild

Hi, I'm looking to rebuild the door locking mechanism in my 2001 996 c4 6mt because I am having problems with the switches. I want to disassemble the lock assembly and replace the microswitches inside and replace the outer door handle microswitches as well. I've found some MPN's from the OEM switch Cherry from a VW website: DK-1-G-UL-A0 DK-1-G-TR-A0 http://forums.vwvortex.com/showthrea...-problems!!!-( supposedly VW uses a similar locking mechanism to porsche, can anyone confirm if these switches are relevant to the 996? I've included part of the VW OEM switch data sheet. If this is relevant to the 996, how many of each type would I need? I can't find the cherry switches but I did find a c&k switch from Digikey which has matching dimensions and operating characteristics MPN: ZMS-H-03-130-P00-L-L-C which i could try unless someone has a better switch they have used. https://www.digikey.com/product-deta...166-ND/2044452 Also, where can I get the water/vapor barrier for the door? Cheers, Dave

door seal/vapor barrier here: http://www.autoatlanta.com/porsche-p...section=807-10 # 4 in parts breakdown

Good information, planning to do something similar, since my driver's dorr is acting up.

It would be great to get a source for these switches. I planned to rebuild mine as well, even bought a used latch on ebay as a backup just in case I needed parts. Upon removal and inspection it turns out that the switches in mine were fine except that the domed cover of the switch's hard plastic button had cut a deep groove in the cover of the actuating cam. The cam cover is a pliable plastic, apparently designed to be slippery, but not hard. At any rate, it wasn't the switch but wear within the latch mechanism that was the problem. I decided to fill the groove with JB Weld, lubricate, and run to fail--seems to work fine now. I'll keep my used one as backup but there is no practical means to disassemble and replace the work parts.

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Brilliant - the cheapest Door Lock Fix ever. Just abrade the worn surface well,clean thoroughly and consider a metal filled epoxy? That should last a little longer -assuming it adheres to the worn plastic tenaciously. Thanks for sharing your repair technique with us.

Thanks for the link Dporto. I've looked at a few other manufacturers of switches and it looks like they have all the same dimensions so it must be standard size, which is good because this means the switches shouldn't be hard to find and it means that it is more likely that the VW switch is the same as the porsche switch. brwilson, is there any way you can open up your spare lock mechanism and see if there is a manufacturers part number and verify that it is indeed that Cherry switch? The same one as the switches in the link above. Maybe take some pictures and upload here? Cheers, Dave

So i was thinking about buying a cheap used door lock assembly to take apart to check what is inside. I went to pelican parts and got the MPN: 3B1-837-016-P-M100 and googled it, and VW parts were part of the results. Amazon Amazon http://www.ebay.ca/itm/Door-Lock-Act...pYRCQ3&vxp=mtr Some look almost identical with some minor user replaceable exceptions. Has anybody tried using these parts? The ebay item does look identical (compared to the pics on Pelicans website) and it makes sense that porsche and VW would use the same parts.

Good information, thank you.

I ordered SW719-ND from digikey. There is a webpage where someone used parts from this digikey part to replace the broker parts in the factory switch. Can't remember the site. Might have been a Boxster door.

This video is interesting and helpful regarding maintenance of the micro switch. You Tube

Nice find rporzio! Tomcat, have you fixed your switches yet? The switch you bought looks like the ones I listed above but with wire leads instead of though hole solder pins. I would like to desolder the original switches from the PCB and replace the whole switch but either solution should work. I'm going to get a few switches and hopefully they fit, if that doesn't work at least I'll have the lock unit out so I have a better idea for the correct parts or maybe just order the VW unit based on what I see. I be sure to post my findings once finished.

I am still reaching outside the door and pushing on the latch to lower window. Window tinter broke it and I've been too lazy to fix it. The part I referenced is not plug and play (yours may be). The site, which could be the one above, used parts from the new switch to replace the broken pieces (not the entire switch). I think its the plunger under the rubber seal (it's been a while).

I searched, but it looks like someone took the repair videos offline. IIRC, you need to unbolt the control unit from the door. The problem is one of the microswitches, I think, connected to the alarm. The part number I provided, was the part the video referenced, but the switch wasn't the exact switch. But you can use the plunger, under the rubber cover, from the new switch to replace the old, if this is what is indeed broken. The rubber cover can be replaced if you want to, but it's the plunger that was broken in the video. You can also purchase the entire control unit with all microswitches, but then you have to route/dismount/mount the wires, etc which seemed like a bigger PITA. And probably 20Xs the cost of a microswitch. I can live with the cost, I just don't want to do any extra work.

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Lexvortex, sorry, have been offline for a while. I'll dig through my spare parts and see if I can crack it open, but that VW unit you posted on from ebay sure looks like the one in my 2000 C2, and the used one I ordered from a 98 Boxster.

Thanks brwilson, I would appreciate all the info I can get! Was your lock assembly for the passenger side or the driver side? Tomcat, thanks for the information. I would like to find a direct replacement, I'm pretty sure I know the part specification needed I just need to find a source. I found another great resource thread in which someone did buy a VW bug door switch to replace his porsche unit (it looks like the ones I linked to above) and it is different from the porsche part. So it looks like that part may not fit our needs except for taking the switches out of the VW units. But maybe other VW or Audi door latch units could fit?? (see link below) https://rennlist.com/forums/996-foru...witches-3.html I do know which PCB mounted switches I will be buying but I am having difficulty locating a direct replacement for the switch with the lead wire, which seems to be the common failure part (the one in the video above). I have a part number for it but none of the common vendors seem to carry it. This is for the passenger side door lock assembly. Digikey carries the PCB mount switches. 2 pieces of C&K PN: ZMSH03130P00LLC (3amp version) or ZMSH00130P00LLC (100mA version same as OEM) these have left hand PCB solder lugs and chassis mounts and are made by C&K. There are other manufacturers that make suitable switches too. 1 piece of C&K ZMSH03130P00RRC or C&K ZMSH00130P00RRC these are the same as above but right hand versions 1 piece of C&K ZMSH03130P00KRC this is a right hand side wire lead with panel mounts on the right side. The part numbers are based on what I could see the pics in the link above and this is for the passenger door, the driver side should have two more switches in the lock module assembly (not sure which ones). As well, I called my local electronics store which carries some Cherry brand switches to see if they could order in some of the OEM door switches and they told me they could not order them as they were not for sale in retail?? I think either they had to buy a large quantity or be a manufacturer.

Most of the time it's the external microswitch (Burgess) that's attached by two wires. There's a plastic covered cam inside the latch that drives that switch. When the plastic layer peels off, it takes out the switch too. I had that problem on the left door and just replaced mine with a used genuine unit 8N1837015C from ebay for $35 shipped. The symptom was the window won't stay down for 1/2" when the door is opened. The window will go down for 1/2" when the outside or inside handle was pulled. I disassembled the whole switch and tested all the microswitches and the motor. I'm lucky that I got a good unit. Lubed up everything and installed it. Works like a charm. All the other 3 (cherry) microswitches inside the lock on the circuit board seldom fail. Maybe cold solder joints but mechanically those don't seem to fail. You may also want to consider 3D1837015, which is the 997 version. Looks very similar and have 9 pins. I was gonna try that if the used one from ebay didn't work out. This geniune one can be had for $50 used and $150 new. Look for 1837016 if you need the right side latch.

Another useful thread on this topic. https://rennlist.com/forums/996-foru...witches-3.html

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Try these numbers on ebay. The parts look correct. I haven't tried them so not 100% sure. 3bd998785 (for left door) 3bd998786 (for right door)

This looks like the 997 style. Looks very similar to the 996 latch. The video also show the problematic external microswitch got replaced with an improved version. You Tube

Hi Ahsai, thanks for all the links! I've ordered the right door microswitch, 3bd998786 (for right door) as well as the C&K switches I mentioned earlier. Hopefully they are the correct fit. I'll post back with results when i replace the switches. Cheers, Dave

Look forward to seeing what you find. I think the more troubling failure is the cam that drives that switch. Once the plastic coat on the cam is ripped, no easy ways to pair that and a new latch is needed (at least the mechainical part).

So I've finally got all the parts in for the door locking mechanism rebuild and found time to take apart the door. The switches I bought were the ones listed at the beginning of the thread and the ebay switch listed. C&K ZMSH03130P00LLC C&K ZMSH03130P00RRC bd998786 from ebay I took apart the locking mechanism and found that the internal switches were in excellent shape and the exterior switch that is normally the problem also seemed to be in decent shape, there was some wear on the button but the rubber seal was still intact and the insides of the switch was clean. After some trouble shooting, I found that it was the solder joint for the ground connection that had failed and was intermittent. I resoldered the joint and everything now works fine. I did replace the external switch due to the fact that the button was wearing down and the new switch I bought had a metal tab which should last much longer. With a bit maneuvering it fit perfectly in place of the old switch and functioned correctly.

Glad that bd998786 switch works. The solder joints look pretty bad in your photo. The one on the upper left looks cracked.

Yep, the solder joint you pointed out, upper left of the photo, was cracked. I reflowed all the solder joints and made sure there was a good connection before putting it back together. I'll probably end up doing the driver door lock soon as I'm sure that the exterior switch is much more worn than on the passenger side.

For intermittent issues, I am wondering if it is the switch or if it is cold solder joints. I dont know if I should buy the parts first or pull it apart first.

Sometimes it's a mechanical issue with the door latch, not always due to the micro switch.

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It ended up being Cold Solder Joints. I saw the cracked joint. I removed all the older solder and re-flowed fresh solder on all the joints and switches. My micro-switches looked like they were in good condition. I cleaned up everything, so hopefully I dont have any issues with the passenger door lock anytime soon. I ordered 2 microswitches from Mouser.com. They ended up being cheapest there. Cost $15.03 shipped for 2. These switches go bad from time to time, so I now have the parts for whenever they go bad. Very cheap compared to the cost of the entire lock. I would feel comfortable replacing any of the micro switches. I stripped the electrical section of the lock all the way down to its core.

These general issues are on numerous threads but it takes some searching and lots of reading to find them. In the meantime I have found an amazing video, 51 minutes long, about taking apart, inspecting, and reassembling a VW door lock mechanism that is very similar to the 996's. If you are at all considering doing this work, this video is a must. Key points from my PoV: 22:00 - detail of inside of electrical half of the unit 26:40 - worm slide and what it does 38:00 - reassembly of the unit from all separate pieces into the whole, and how to test at each stage You Tube

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There are many things worth the time and effort to rebuild, but out of all the locking assemblies I've worked on, replacement is the best course of action IMHO.

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I agree. At least with my experience I had at least one, likely two failed microswitches and so replacing the entire unit just made more sense.

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I also agree, particularly if it is the drivers door. When you go to unlock and stand there and pull on your handle 20 times to try and get the door open, lock, unlock repeatedly and have that truly sinking feeling that you can't get your door open...time for an entire door latch mechanism. I sprung for an OE door latch mechanism because the old one worked for 20 years. Just pony up on this one and move on. https://rennlist.com/forums/996-foru...-detailed.html

To follow up, I got some time today to look at the door lock again with the benefit of the video of the VW lock mechanism. I believe I had misaligned a lever in one section with a hole in the other section while reassembling previously. Everything else was fine. Put it back together and it works great including no more flickering of the red lock LED on the dash. The original issue I had was definitely cold solder joints on the PC board. They were easy to see. The video helped a lot to make sure the two halves of the lock are in the same state while reassembling (locked or unlocked) and the tests along the way to determine that the pieces are working together.

Just finished this job on my 2001 996. The 2/3/2020 post by mklein9 is superb in terms of showing how the mechanism works. However, the VW part is a bit different from the Porsche OEM in that it is not possible to take off the cover to the electronics section without first taking out the torx screw that holds the locking mechanism assembly together. The Porsche unit has a forked plastic part that inserts both above and below the worm gear that drives the lock. So, if you don't take this torx screw out first, the whole assembly will pretty much blow apart on you when you pull the cover off and you'll spend a good 30 minutes or more figuring out how to put everything back together. Also, you need to pay close attention to how the locking mechanism works in mklein9's video. If you don't pay attention to this, you'll assemble everything and find that the the main cam in the door latch which holds the door closed will rotate using a screwdriver, but it will not latch. That's because the metal tab attached to the unit with that torx screw you undid (the unit has two springs tensioning it: a little circular spring and a heftier right angle spring) is not engaged with the metal receptacle in the other half of the unit. This means you can't lock and unlock the unit without taking the whole thing apart again. You'll know you've done it right if you can latch the unit using a screw driver and unlatch by pulling on the door-pull lever. Do this before putting it back in the car to save yourself some curse words! Finally, I ordered a couple of microswitches from Digikey that were recommended at various places here on Rennlist as good replacements for the door latch switch (CKN10166-ND and SW719-ND). Neither of these has the right package to fit into the receptacle in the OEM mechanism. There are a couple of plastic pins that stick out of the OEM switch that fit into holes in the metal casing. If you don't get a properly configured switch, it won't fit. The OEM switch is relatively easy to take apart by prying open 4 small tabs on the package (use at least 2 screwdrivers when you do this or you'll drive yourself crazy). The problem with this switch is that it has a plastic plunger that rubs against a metal cam every time the door is opened. After many years, this plastic wears down so that the plunger no longer gets pushed far enough to close the switch. In my unit, it went from being an open circuit to having ~50 ohms of resistance. So, it was still a two state switch. But even 50 ohms was too much. The window would no longer jog down when the door was opened at that red light on central dash locking rocker switch was always on. If you can replace the plunger, the rest of the switch will work fine. Unfortunately, neither of the listed Digikey parts have the right length plunger. One was too short and the other too long. So, a sanded down the OEM plunger to make a nice flat end to it. Then I used an exacto knife and bit of patience and cut off the rounded top from plungers of one of the new switches (you have to rip the hell out of the new switch to get the plunger out - it's not made like the OEM with openable tabs. If you do this, be careful to cut far enough away from the plunger that you don't damage it when you open the package). Then I used some epoxy to glue it to the OEM plunger. This worked great. The OEM switch is a Burgess with the markings 47/00 on it. That's it. It turns out that Johnson Controls in Hong Kong makes it. I contacted them and they told me the switch is custom made for Porsche. They refused to sell it to me or tell me any more information about it. So, this $2 part is being used by Porsche to force you to buy a several hundred dollar unit due to a bad design! So sad.