2010 Jetta door latch fix.

soot1

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Nov 6, 2009
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TDI
Currently none. Formerly: 2010 VW Jetta TDI 6M, 1993 Dodge Ram W250 Cummins 5M 4WD, 1990 VW Jetta Diesel 5M, 1986 VW Jetta Diesel 5M, 1980 VW Uabbit Diesel 4M. Currently driving 2018 Toyota 4Runner SR5 4WD.
Over the past two years or so, I've been experiencing issues with the driver's door latch. In the beginning, my specific symptoms were that every now and then, when locking the door with the electronic key fob, the door would not lock or unlock. It was always only the driver's door, all others work just fine. The red LED in the driver's door would stay on permanently instead of flashing when attempting to lock the door. When I pulled the door handle, the door would open and the alarm was activated. Alternately, when unlocking the door, the LED would go out, indicating the door is open, but it was still locked. As time went by, this became more and more frequent, so I made it a habit always to check whether the door is locked before leaving the vehicle. The next symptom that also appeared insidiously was that the alarm at one point no longer sounded when the door was open with the LED on. Sometimes, when I didn't succeed to lock the door on a first try, I would unlock it and lock it again. The second attempt was usually successful. However, as time went by, even this trick stopped working , and about 3 months ago, the key fob stopped working altogether. At that point, the only way to lock or unlock the driver's door was to insert the key into the lock and turn it.

I did some research on this issue, and there are some reports of defective microswitches in the electrical part of the latch. This sounded plausible, as the microswitches tell the on-board computer whether the door is open or closed, and locked or unlocked. After viewing a couple of videos on Youtube on how to remove the lock cylinder, the door skin and how to take the latch apart, I decided to give it a try. Originally, I had a new latch assembly (VW part number 3B1837015AT) on my list of parts I planned to buy with my $500 goodwill dealer card, but I figured if I can fix the old one, I'll save myself at least $140, which is what I would pay for it at keffervw.com (lowest on-line price I could find). So this morning, I went to the garage and began removing the latch. First, I removed the plastic shield from the door edge. You just peel it off, no tools required, it holds to the door with several snap-on buttons. Next came the removal of the door lock cylinder, and it was also a breeze, I encountered no problems (you will need Torx 20 screwdriver). Next was removal of the door handle cable from the handle. Before I pulled the cable end from the groove, I marked its position with a silver pen (excellent contrast on the black plastic). This step will save you some headaches when putting everything back together. Next was removal of the door handle and a Torx 20 screw that holds the door skin to the lock cylinder subframe. My next move was to duct-tape all edges of the door and front fender to protect them from accidental dings or scratches. Removal of the door skin was next, and it is also a pretty straightforward operation. Just take note of which type of screw goes to any particular location, as there are three different types. All screws are Torx 30. After removing the door skin, the latch comes into view. The removal is also fairly easy. Start with the two triple-square screws (6 mm) that hold the assembly to the door. Once you remove them, push the latch assembly with the shield upwards and then towards the front of the vehicle (the whole assembly hangs on a tab, similar to a picture on a wall). Next, remove the cable that opens the door from inside. The outer shell of the cable is secured to the latch assembly, and it takes considerable force to remove it. When you are done with that, unhook the end of the cable from the lever. Next, using small flat screwdriver, remove the electrical connector. You will notice that the rain shield is secured to the latch assembly with three snap fingers. Remove the rain shield, and you are left with the bare latch assembly.

I then went upstairs to take the latch apart. It is composed of two sections, mechanical and electrical. They are held together by one Torx 15 screw. I removed this screw and wiggled the two sections apart. Being certain the problem is somewhere in the electrical section, I proceeded to take it apart. The electrical section is made of two clamshells that are held together with several Torx 10 screws. Once I removed them, the subassembly came apart. Inside is a small printed circuit board that holds three microswitches and the electrical connector. Another remote microswitch is located in the mechanical section, and is connected to the circuit board with rather rigid wires. Since I suspected the microswitches to be the culprit, I proceeded to measure with an ohmmeter whether they function correctly. They checked OK, so I focused my attention on the servo motor, which is the only other electrical component in the shell. Using an ohmmeter, I measured DC resistance of the winding, and that's when I found something strange - 1200 ohms. The resistance should be a couple of ohms at the most. So, next I pulled a power supply, set it to 12 V, and connected to the motor. It turned about half a revolution, and stopped. Culprit identified. Curious what can possibly be wrong with a small DC motor, I proceeded to take it apart. It is typical small DC motor made by Mabuchi, part number FC-280PD-20150. The metal case of the motor that holds the magnets and rear bearing has two tabs that secure the front end of the motor, which is made of plastic and holds the front bearing and the two brushes. It took some effort to bend the two tabs out of the way. I then pulled the metal casing with the rear bearing off the shaft, and the damage was in plain sight: the commutator was completely blackened where the brushes came into contact with it. I suspect that during the assembly, bearing grease somehow ended up on the commutator, and the arcing that is normally present when the motor runs turned the grease into clump of carbon. I then carefully removed the brushes from the commutator and slid the entire plastic front part of the motor as far as I could to get better access to the commutator. Using a narrow strip of 600 grit sandpaper, I removed the carbon deposits from the commutator until only clean copper showed. I then removed the brushes from the front cover and cleaned them too. Next, I washed the inside of the front motor cover in solvent, as it was all covered in black dust and bearing grease. Once everything dried up, I reassembled the motor and hooked it up to 12V. As expected, it came back to life. Quick ohmmeter check showed 3 ohms, which is what I would expect. I then reassembled the electrical section, attached it to the mechanical section, then the rain cover, and went downstairs to the garage to put it all back together. About an hour later, when the latch was inside the door, the door skin, handle and lock back in place, the moment of truth came when I shut the driver's door and pushed the "LOCK" button on the key fob. It worked flawlessly !!!!!

Moral of the story - if your door latch isn't working properly and you pull it out and find out the microswitches are OK, check if the servo motor might be the root cause. Of course, now that the latch is working, I'll have to come up with something else to buy with the money I set aside for the new latch. Also, my apologies for not attaching any pictures. I tried to finish as soon as I could (it still took almost all day), plus my hands were greasy and grimy all the time, so touching a camera was out of the question.
 

jetlagmech

Veteran Member
Joined
Oct 1, 2009
Location
Toledo, WA
TDI
2010 jetta
Thank You Just saved me $120

replaced my rear lock couple years ago, now the front pax is acting up. I still had the old rear one so disassembled it and just as you described the little motor had 400 ohms. the tabs holding the little motor shell together had some trouble with but eventually got it. might have damaged it but it is a spare now. will be able to do it next time easy. The brushes and commuter black with carbon. cleaned up and now 3 ohms across motor. so now I know I can fix the front one without buying a new assembly.

And now have same problem as you. that door latch assy was my plan on spending some the VW goodwill visa card money for use at dealer. This is a terrible problem.......having so much money and dont know what to buy.

Maybe I can take my spare one apart again and take a few pics.
 

soot1

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Joined
Nov 6, 2009
Location
Houston, TX
TDI
Currently none. Formerly: 2010 VW Jetta TDI 6M, 1993 Dodge Ram W250 Cummins 5M 4WD, 1990 VW Jetta Diesel 5M, 1986 VW Jetta Diesel 5M, 1980 VW Uabbit Diesel 4M. Currently driving 2018 Toyota 4Runner SR5 4WD.
Thank You Just saved me $120

replaced my rear lock couple years ago, now the front pax is acting up. I still had the old rear one so disassembled it and just as you described the little motor had 400 ohms. the tabs holding the little motor shell together had some trouble with but eventually got it. might have damaged it but it is a spare now. will be able to do it next time easy. The brushes and commuter black with carbon. cleaned up and now 3 ohms across motor. so now I know I can fix the front one without buying a new assembly.

And now have same problem as you. that door latch assy was my plan on spending some the VW goodwill visa card money for use at dealer. This is a terrible problem.......having so much money and dont know what to buy.

Maybe I can take my spare one apart again and take a few pics.
It is good to see that someone else was able to duplicate the failure mode I found in my door latch. In my years of engineering experience, I never saw a small electric motor fail in this way. In fact, this was the very first failure of a DC motor this size I saw in my life. Commutators and brushes may get worn out with heavy usage, but they still remain clean. Buildup of that non-conductive layer points to the presence of some foreign substance on the commutator that wasn't supposed to be there. When I saw that "MADE IN VIETNAM" sign stamped on the motor, all I could think of was "dear Lord, what were the Japanese thinking to make the motors in a place like that? (Mabuchi used to make all their products in Japan). I am 100% certain that if these motors were made in Japan, we wouldn't be dealing with these failures.

Anyway, as I mentioned in my original post, I had hard time bending the two tabs on the motor as well. After numerous failed attempts to force them out of the way with small flat screwdriver, I decided to weaken the "knee" of the bend with my Dremel motor fitted with a thin grinding wheel. That idea worked just fine. Then, when the motor shell came off the shaft, I realized there is fairly large contact area between the metal shell and the plastic front end that could be used to superglue the two pieces together should the two tabs fall off completely after weakening the "knee". In the end, when I was putting the motor back together, one of the tabs did break off, so I used a few small drops of superglue to hold the motor in one piece.

I also attempted to find this exact same motor for sale anywhere on the web to make the repair much easier, but all I could find was a motor with much shorter shaft and without the gear. However, even if I could find the exact replacement, it would likely still be plagued with the same problem as the original one, and chances are it would also fail within the same time, which was approximately 3 years. As for the idea to take the now repaired assembly apart again and take pictures while you do so, I would suggest you take pictures (or better, a video) of how you fixed the front door latch when you decide to repair that one. Also, I just recalled that the driver's door latch has one Torx 8 screw I forgot to mention earlier. In any case, do let us know how the front door latch repair goes.
 

OMALLEY_808

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Joined
Jul 17, 2014
Location
Canada
TDI
2006 JETTA TDI
I fixed my front passenger door this exact same way about 1 year ago and it is still working perfectly!

As for those tabs on the motor the best was for me was to use needle nose pliers and bend them out. to disassemble the motor. Also make sure to use some very light grease or a thicker oil on the worm gear so that the motor doesn't have to work very hard.
 

jetlagmech

Veteran Member
Joined
Oct 1, 2009
Location
Toledo, WA
TDI
2010 jetta
The only problem I had besides the pain of the door skin and handle, I had to partly disassemble the latch a 2nd time. when installing the black manual latch part of the assembly back onto the white plastic electrical part, I didn't get a little metal arm into the correct spot. the little arm is on a red plastic lock lever. Taking the door skin off and on was a lot easier this time.
 

brianstrange

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Joined
Aug 22, 2006
Location
Tyngsboro, MA
TDI
2006.5 Jetta DSG Auto Pkg 1
Are your problems with the latch, or the locking actuator? It sounds like they are part of the same assembly, but I was hoping to clarify. My issue is the right rear door lock actuator is not triggering (from any door switch) The rest of the door locks work properly, and I confirmed the RR lock switch is communicating.
 

jetlagmech

Veteran Member
Joined
Oct 1, 2009
Location
Toledo, WA
TDI
2010 jetta
the problem is with the electric actuator. it looks like a little matchbox car motor. its a shame VW (and many other makers now) doesn't have a manual lock button to use when actuator is out. But better than the newer VW's, the actuator assy is glued together instead of screwed together like ours.

The latch and actuator are together in one assembly, that you seperate after removal, to clean the little motor.
 

studebaker

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Joined
Aug 8, 2005
Location
Lake City, Fl
TDI
2006 Jetta pk 1
We have an 06 Jetta that is starting to have the door lock issue. My wife works at a state prison and it is a rule (of course!) that all vehicles be locked when not in use.
The Jetta was checked this morning and she was told her car wasn't locked. She tried it manually and with the key fob and it wouldn't lock. I picked up the car and have tried it numerous times since and it locks every time!
So, does the drivers door actuator activate all four doors? I may have to take it apart and start from that point.
??
Thanks!
 

jetlagmech

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Oct 1, 2009
Location
Toledo, WA
TDI
2010 jetta
on mine that is the way it goes out. starts getting intermittant then only intermittantly will work then finally wont work at all. mine for a long time would lock fine but not unlock.
 

soot1

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Nov 6, 2009
Location
Houston, TX
TDI
Currently none. Formerly: 2010 VW Jetta TDI 6M, 1993 Dodge Ram W250 Cummins 5M 4WD, 1990 VW Jetta Diesel 5M, 1986 VW Jetta Diesel 5M, 1980 VW Uabbit Diesel 4M. Currently driving 2018 Toyota 4Runner SR5 4WD.
She tried it manually and with the key fob and it wouldn't lock.
Are you saying she tried to lock the driver's door by inserting the key into the lock, turning the key, and the driver's door didn't lock? Or, was it one of the remaining three doors that wouldn't lock when she locked the driver's door? The way the driver's door lock is designed on 2010 models allows you to lock that one door even without the battery being connected - there is a purely mechanical link between the inserted key and the latch, so there is no way she would not be able to lock the driver's door, unless the mechanical part of the latch assembly failed, and I haven't heard any reports of that happening. If any of the remaining three doors won't lock when you try to lock them by inserting the key into the driver's door and turning it, you can still lock them by removing that little rubber cover with the lock symbol on it from the side of the door, inserting the key, tipping the latch into locked position, and shutting the door. Check your manual, there is an explanation how this works. However, if any of the remaining three doors don't lock (or unlock) when you manually lock or unlock the driver's door, that door that doesn't lock/unlock has defective latch, and chances are it is the motor that failed. And to answer your question - yes, the driver's door actuates all four doors if the battery is connected. Without the battery connected, inserting the key into the lock and turning it will only operate the driver's door.
 
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studebaker

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Joined
Aug 8, 2005
Location
Lake City, Fl
TDI
2006 Jetta pk 1
Inserting the key into the drivers door will lock and unlock that door. The problem is the others don't lock. Prisoners won't mind! they just need to find a way in.
Yes, the others will lock mechanically by removing the plug you mention. But that is more of an emergency method, and I need to fix it so it operates properly, with the key fob or drivers door lock switch. tho!
I think I will try something simple first, remove and clean the battery cables just to be sure that part of the process is ok.
I have noticed that when I lock it with the key fob, a few minutes later I will hear a beep, just like you hear when it is locked with the fob. I checked and the doors are still locked so I don't know why it suddenly started doing that.
Thanks for all the help!
 

soot1

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Nov 6, 2009
Location
Houston, TX
TDI
Currently none. Formerly: 2010 VW Jetta TDI 6M, 1993 Dodge Ram W250 Cummins 5M 4WD, 1990 VW Jetta Diesel 5M, 1986 VW Jetta Diesel 5M, 1980 VW Uabbit Diesel 4M. Currently driving 2018 Toyota 4Runner SR5 4WD.
Inserting the key into the drivers door will lock and unlock that door. The problem is the others don't lock. Prisoners won't mind! they just need to find a way in.
Yes, the others will lock mechanically by removing the plug you mention. But that is more of an emergency method, and I need to fix it so it operates properly, with the key fob or drivers door lock switch. tho!
I think I will try something simple first, remove and clean the battery cables just to be sure that part of the process is ok.
I have noticed that when I lock it with the key fob, a few minutes later I will hear a beep, just like you hear when it is locked with the fob. I checked and the doors are still locked so I don't know why it suddenly started doing that.
Thanks for all the help!
When my car started acting up, I saw all sorts of weird things happen, including the failure mode you are experiencing, when the driver's door will lock correctly, but the rest of the doors will remain open. If my memory serves me well, I think I even had that extra horn beep about a minute after I locked the door. Bottom line - that defective door lock will throw all sorts of codes that will make the car act in a really strange manner. As for cleaning the battery cables - if you can start the car without any issues, chances are the contacts are clean, so I wouldn't spend much time on that. Go straight for the driver's door lock. Once you fix it, all the weird behavior will be gone. Also, one more word of advice - before I started the work, I looked up on youtube a couple of videos. One was dealing with how to remove the door skin and the lock assembly, but the one I consider absolute must to view before you dive into the repair is this one: https://www.youtube.com/watch?v=hA_igZnCBPY. The author of that video takes apart and gives a very detailed tutorial about a lock from his 2000 Jetta, but I found only very minor differences between his lock and the one that's in my car. The video is almost one hour long, but after viewing it, you will not only be able to fix your lock, but also understand very well how it works. He has another video on youtube that shows how to remove the lock from the door, but that's not too relevant to our cars because on our vehicles, you access the lock from the outside by removing the outer door skin, whereas his vehicle allows access to the lock only from inside the car. Another video that he posted on youtube deals with particular functions of the electrical switches, but you won't need that knowledge to fix the module. My suggestion to you would be as follows: 1. remove the lock, 2. take the electrical section apart, 3. inspect all solder joints for fractures, 4. measure all four microswitches, 5. disassemble and repair the motor. I am almost certain performing all these steps will eliminate all of the issues you are seeing. Good luck, and let us know how it went when you are done.
 

jetlagmech

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Joined
Oct 1, 2009
Location
Toledo, WA
TDI
2010 jetta
each door has a lock button. did you try useing them?? make sure that its not just a problem with the drivers door wires. probably the actuators. that is a very common problem. the first one will take you half a day but after that the others will take you just a couple hours each.

sorry you are so far away or I could give you a hand. I like watching other people work. I could hold a flashlight and point at things.
 

studebaker

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Aug 8, 2005
Location
Lake City, Fl
TDI
2006 Jetta pk 1
2006 Jetta TDI
OK, thought I'd give an update on this. I pulled the outer door panel off using the intstructions in the VW Jetta service manual. I did not have the special hook screwdriver looking tool and ordered one (T10118). I pulled the panel without it. Took the lock mechanism apart and everything seem fine. I could not see any issue visually with the circuit board. I ohm'd the little motor leads and got 5 ohms. I did not see any way to pull the motor housing apart. I wound up ordering a Dorman lock mechanism off of Amazon. With shipping 130.00. It came in yesterday so I installed the new one. I wound up taking out the little screw that holds the door handle back plate in place so I could install that apart from the door skin. Then installed the door skin back on. Tested everything and the locks seem ok now.
Surprised the outer door skin came off that way, never seen that before! Also, the tool I ordered had not come in so I did the assembly-reassembly without it. Don't know why it is really needed.
Thanks for all the help!
 

TC282AVIATOR

Member
Joined
Sep 20, 2007
Location
GA
TDI
2001 Jetta
2010 jetta with three of the four doors not locking , pulled all three lock actuators , all the micro switches were fine. So I removed the small electric motor, opened them up and found they had very heavy carbon build up . Cleaned the brushes and the carbon off the commutator. Before putting the motors back together it took my dremel and made a small notch in the plastic head , then when you slide the metal case back on you can dimple it , which will hold it securely in place. All three worked great . Much better then spending 350 on new actuators .
 

bobthefarmer

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Joined
Aug 11, 2013
Location
Indianapolis
TDI
2006.5 Jetta Mk 5 192K miles; 2012 Car of the Year, Passat Tdi SE+Nav in blue nightgown, shod in 18 inch heels
Great Thread. I recommend a "StickY" for this fix. I have an "intermittent" driver's door lock actuator. When you have a concealed carry, you want your doors to lock for you reliably. I will be taking my skin off soon. Maybe I'll get some pictures!
 

bobthefarmer

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Joined
Aug 11, 2013
Location
Indianapolis
TDI
2006.5 Jetta Mk 5 192K miles; 2012 Car of the Year, Passat Tdi SE+Nav in blue nightgown, shod in 18 inch heels
Keep your "Beep" notification on for each key FOB. I learned my car would not give me may departure "Goodbye, I'm locked" notification and found the offending door by opening it!
 

nokivasara

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Joined
Jan 25, 2008
Location
Sweden @ Lat 61N
TDI
Tiguan 4-motion, Golf mk7
What a great thread!
We have an intermittant lock fault on the drivers side, the microswitch works because the MFD and interiour lights turn on and off like they should when the door is opened.
 

bobthefarmer

Veteran Member
Joined
Aug 11, 2013
Location
Indianapolis
TDI
2006.5 Jetta Mk 5 192K miles; 2012 Car of the Year, Passat Tdi SE+Nav in blue nightgown, shod in 18 inch heels
Some Pictures of Motor

It is good to see that someone else was able to duplicate the failure mode I found in my door latch. In my years of engineering experience, I never saw a small electric motor fail in this way. In fact, this was the very first failure of a DC motor this size I saw in my life. Commutators and brushes may get worn out with heavy usage, but they still remain clean. Buildup of that non-conductive layer points to the presence of some foreign substance on the commutator that wasn't supposed to be there. When I saw that "MADE IN VIETNAM" sign stamped on the motor, all I could think of was "dear Lord, what were the Japanese thinking to make the motors in a place like that? (Mabuchi used to make all their products in Japan). I am 100% certain that if these motors were made in Japan, we wouldn't be dealing with these failures.

Anyway, as I mentioned in my original post, I had hard time bending the two tabs on the motor as well. After numerous failed attempts to force them out of the way with small flat screwdriver, I decided to weaken the "knee" of the bend with my Dremel motor fitted with a thin grinding wheel. That idea worked just fine. Then, when the motor shell came off the shaft, I realized there is fairly large contact area between the metal shell and the plastic front end that could be used to superglue the two pieces together should the two tabs fall off completely after weakening the "knee". In the end, when I was putting the motor back together, one of the tabs did break off, so I used a few small drops of superglue to hold the motor in one piece.

I also attempted to find this exact same motor for sale anywhere on the web to make the repair much easier, but all I could find was a motor with much shorter shaft and without the gear. However, even if I could find the exact replacement, it would likely still be plagued with the same problem as the original one, and chances are it would also fail within the same time, which was approximately 3 years. As for the idea to take the now repaired assembly apart again and take pictures while you do so, I would suggest you take pictures (or better, a video) of how you fixed the front door latch when you decide to repair that one. Also, I just recalled that the driver's door latch has one Torx 8 screw I forgot to mention earlier. In any case, do let us know how the front door latch repair goes.
Took my 2006 Jetta to task yesterday. My faulty door was Fwd Passenger door. I must learn how to unskin the outer door better. Important to remove outer door Handle prior to disassembly.

Upon removing the little motor, I also found it tedious to break the knee of the metal tabs, but they succumbed to my will. Mine did not look too carboned up inside and no dust. However, it was intermittent and the armature was quite tarnished. After removing the shaft of the motor, I rotated it in a drill chuck and rubbed a Pink Pearl Eraser on the contact area of the armature as it spun in the drill. I did not touch up the brushes, as I am not a jeweler and have no patience for the fine extraction of the brush springs. All went together well, with undo amount of patience. The door skin installation works better with the latch partially assembled to the skin, prior to installation. Thanks for the "Fix" Soot1 and Studebacker and JetLagMechanic. I took some pictures, but not of the detail of the motor bits. All in all, me thinks a latch purchase may be better, but someone should open a shop to just fix these little bastards.

Could the Motor be purchased and the existing log armature be installed in a new Motor after cleaning? I uploaded pictures, but can't get them on this thread! This will likely work for all post 2000 VWs as they all seem to have very close DNA in this area. I found you need a T15, T10, and T5 for all the screws. It was frustrating to get the T5 tool! Why they couldn't standardize! This FIX takes a lot of patience!

 
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summersofftoride

New member
Joined
Apr 22, 2017
Location
CT
TDI
2006 Jetta
Will this fix work if the key fob, and interior switches don't work on any of the doors? I have the codes from my buddies vagcom but not accessible right now. they were low voltage issues with doors and airbags. still have to check the battery with voltage meter. The door issue was known before I bought the 06 tdi jetta last week. We did try to put a tender on the battery for a while which did nothing.
 

jetlagmech

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Joined
Oct 1, 2009
Location
Toledo, WA
TDI
2010 jetta
I had to buy a new set of star tips when I disassembled my CD player after it went out to get my CD's back. So I already had a set that went small enough for the door actuator assy. But why they had to use 2 separate sizes on the case half I don't know.
 

bobthefarmer

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Aug 11, 2013
Location
Indianapolis
TDI
2006.5 Jetta Mk 5 192K miles; 2012 Car of the Year, Passat Tdi SE+Nav in blue nightgown, shod in 18 inch heels
Nope, wrong issue

Will this fix work if the key fob, and interior switches don't work on any of the doors? I have the codes from my buddies vagcom but not accessible right now. they were low voltage issues with doors and airbags. still have to check the battery with voltage meter. The door issue was known before I bought the 06 tdi jetta last week. We did try to put a tender on the battery for a while which did nothing.
Unless both doors are shot, then maybe. Good luck. I would purchase a LH door actuator assy. You need that door most.
 

jetlagmech

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Joined
Oct 1, 2009
Location
Toledo, WA
TDI
2010 jetta
Old thread but here's an update. I had to do the front passenger door again. stopped working last week. Brushes had carbon up again. cleaned it up and it works good again. Gets faster every time I do it. Even with having to remember how from several years ago.

Strange that the one that operates the most, drivers door, has never given me any trouble. after the first one went out, I changed the setting to not auto lock and unlock all doors every drive, thinking that would reduce wear and tear
 

soot1

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Nov 6, 2009
Location
Houston, TX
TDI
Currently none. Formerly: 2010 VW Jetta TDI 6M, 1993 Dodge Ram W250 Cummins 5M 4WD, 1990 VW Jetta Diesel 5M, 1986 VW Jetta Diesel 5M, 1980 VW Uabbit Diesel 4M. Currently driving 2018 Toyota 4Runner SR5 4WD.
When I did the original write-up years ago, I was endlessly pondering what could possibly be behind the fouling, and I came to the conclusion that it was some type of hydrocarbon (grease or oil) that somehow ended up on the brushes and commutator. The brushes and commutator must be completely free from any contaminants to function reliably. Then, I realized one more thing - the rotor of the motor only makes about 3-4 full turns before it comes to a screeching halt when the plunger reaches the end of its travel. DC motors draw the highest current with the rotor at a standstill, then, as the rotor reaches its nominal speed, the current draw drops down significantly. In this particular case, the stall current is 4 A, but when the motor reaches its nominal speed (11000 RPM), the draw drops to something like 0.1 A. When the motor is operated for such a short period of time as this one is, the stall current doesn't have the opportunity to drop too much from the 4 A before the motor stops. This is probably the second contributing factor because the fouling of the commutator that inevitably happens during these high-current start-ups is then gently polished away by the brushes when the motor reaches its nominal speed. However, this one never does. It only sees those high-current spikes and nothing else.
 

Brett San Diego

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Jun 25, 2013
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San Diego
TDI
02 Jetta wagon manual
Just keeping this post going strong 5 years on (because it's very good). I just acquired an '06 Jetta sedan that had a non-functioning driver's door lock. This post gave me the knowledge and motivation to get in there. Upon opening up the electrical section and removing the motor, I realized I didn't have any contacts to put 12 V to it to test so I plugged it back into the tabs and put power to it. It spun just fine. I tested the microswitches, and all functioned fine. Everything looked good. Now, I was mad because I couldn't find anything wrong. Anyway, I put some lithium grease on all the moving parts and put it all back together. I decided to test on the car before reassembling everything, and magic, it now worked. I didn't do anything, but I must have done something. Maybe it had a bad contact either at the connector or at the tabs going into the motor. I have no idea. I'm just happy the door lock works now. Really appreciate the post.


Brett
 

Brett San Diego

Veteran Member
Joined
Jun 25, 2013
Location
San Diego
TDI
02 Jetta wagon manual
Well, I spoke too soon. The driver's door lock worked for an afternoon, but then stopped again. I think spinning the motor at full speed wore the varnish off the commutator just enough to allow the driver's door lock to work momentarily, but it wasn't a long term result. The seller had only mentioned the driver's door not locking, but I checked and found both passenger doors were not locking on occasion as well. So, I took out the front passenger door lock and fully disassembled the motor as stated, and sure enough, the commutator was blackened. Again, the motor would spin freely when 12 V was applied, but when reassembled, it didn't produce enough torque to operate the lock. There is a coil spring on the arm outside of the box that the mechanism has to work against. At first, I tried weakening the spring by bending the ends closer to one another, but testing on the car showed that the motor was so weak that it wouldn't work unless nearly all the tension was removed. I considered just removing the spring. The lock worked fine without it. The motor has to work pretty hard against it, and I'm not convinced it's necessary. The spring ensures that the arm remains locked in place at either end of its travel so that the door stays locked or unlocked. Without the spring, maybe vibration from driving can cause the mechanism to move and the door to lock or unlock on its own, but I'm not wholly convinced.

At any rate, I was able to take the motor apart, clean up the commutator with 2000 grit sand paper and reassemble. I wasn't able to reuse the original metal tabs to hold the motor together, so I took the advice of an earlier poster and used a dremel tool to deepen the notches on the plastic, then peened the metal case with a chisel to lock the plastic face piece in place. Worked OK.

Brett
 
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Brett San Diego

Veteran Member
Joined
Jun 25, 2013
Location
San Diego
TDI
02 Jetta wagon manual
After disassembling 3 door locks 4 times in 2 days, I consider myself an expert in Mk5 door latches. By lock #3 I figured I'd take some pics and include a couple details to ease disassembly for anyone still reading this thread.

No pics of it, but it is a battle peeling back the original tabs that hold the motor together. My best technique was to use a jewelers screwdriver to deform the tab's tip just enough by jamming the screwdriver into the plastic right at the end of the tab and twisting back and forth so that I could then use a small needle nose plier to grip the metal and peel it back. It destroys the tab, so you have to take further measures to put the motor back together. That's described in the imgur post linked below.
Also, as I pulled the first motor apart, there was something holding it together. I couldn't easily just pull the armature out of the case. After a minute of concern that I was breaking something by just pulling it out... I just pulled it out. It turns out that "something" was magnetism. LOL Once you have the motor's plastic face plate free, just pull the armature out of the case. There will be magnetic resistance. And, just pull the plastic face plate up the shaft toward the gear to expose the carboned up commutator. There's a little bit of resistance as the brushes slip over a lip on the commutator, but it all stays together just fine. Just pull.

I don't see how to post pics, so here's a link to an imgur post with all the pics and descriptions.

https://imgur.com/a/M9WsAng

Brett
 
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