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Discussion Starter #1
I have a rear right door lock mechanism that is not opening from the outside, even directly pulling on the external handle metal cable with my hand. I believe the part# is 3B4839016B, but I cannot verify without tearing the door apart (and that would take considerable time and swearing). My friend had his rear right door lock mechanism replaced on his 2002, and kept the old part, 3B4839016AE (interchangeable with 3B4839016AM, I believe), which is right in front of me. I believe that the electrical board (solder joint issue) was the culprit on his unit, and that's quite easy to fix. Everything else on it appears to mechanically function properly, but I wouldn't know if it's fixable unless I can plug it in.

Anyway, long shot question, but has anyone ever used the newer generation B5 rear door lock mechanisms in pre-2000 cars? My hunch says that the footprint, function, and interface is the same, but that VW made some small tweaks to the electronics. For instance, his circuit board has a protective laminate over it, I'm guessing to minimize shock-based solder joint failure. That alone could cause VW to issue a new part#, I would think.
 

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I think mechanically they are the same, however I'm pretty sure the electrical portion is different, hence the before the split and after the split in 2000 statement on the parts sites.
It's my guess that the window controller motor is what changed and because of that the wiring is ever so slightly different.
Similar to what they did with sunroof motor. The B5.5 sunroof assembly and motor can be used in the B5 but the motor connections are different.
I did a write-up on that a few years back.
But going to back to your question, maybe FrescoGreen01.5, PZ or maybe cuppie can chime in on this.
 

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Discussion Starter #3 (Edited)
I think mechanically they are the same, however I'm pretty sure the electrical portion is different, hence the before the split and after the split in 2000 statement on the parts sites.
It's my guess that the window controller motor is what changed and because of that the wiring is ever so slightly different.
Similar to what they did with sunroof motor. The B5.5 sunroof assembly and motor can be used in the B5 but the motor connections are different.
I did a write-up on that a few years back.
But going to back to your question, maybe FrescoGreen01.5, PZ or maybe cuppie can chime in on this.
Thanks. I tried my best to compare new units online of each revision, and they look almost identical from the outside, from many angles. I've talked to a VW supplier and they were optimistic it would work, and agreed that the microswitch circuit is likely the major (or only) change. Unless I get lucky and find the one or two people who has tried this, I might be forced to rip everything out and try it myself. No money to be lost, just a ton of aggravation.

EDIT: FYI, part of the reason for me asking is VW doesn't produce the B model (my car's version) anymore. And, no one seems to still have it in stock (OEM VW). If we have an actual VW dealer mechanic on the site, they must run into this situation where they can't offer a new replacement of the old model. Maybe they have to go to rebuilt options if the new revision doesn't work. Hopefully someone will chime in.
 

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They love changing connector geometries -- try owning a 1996 Audi A4, for which nothing is made and almost everything differs from 1997 and subsequent years. :(
 

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Discussion Starter #5
They love changing connector geometries -- try owning a 1996 Audi A4, for which nothing is made and almost everything differs from 1997 and subsequent years. :(
I just installed the 2002 door lock mechanism, ONLY mechanically (bolted in, hooked up external and internal pull handle cables). The geometry of the bolt holes are exactly the same, the manual child lock turn clip is in the same spot, the latch lines up perfectly with the door frame, the internal handle works fine, the external handle works fine. The electrical connector is identical. So, after I take apart my old one, inspect it to compare to the 2002, and try to clean it up, lube it, and re-solder all the connections, and then re-test, I will make a decision on whether to reinstall the old (if fixed) version, or risk plugging in the new unit. I kind of doubt I will fry something upstream, such as at the motor central cable module, but it's always a possibility if they changed the electrical specs. I've got to believe someone in our PW group has done what I'm proposing, given how often the door lock mechanisms fail on our cars.
 

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Discussion Starter #6
Oh, I might also be able to take my electronics (properly re-soldered) and transplant them into my friend's 2002 lock mechanism, and that would avoid all questions. That's assuming the electronics and interfaces to the plastic parts inside the mechanism remained the same across revisions.
 

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Discussion Starter #7 (Edited)
Tore the lock mechanism apart yesterday. I re-soldered the circuit, and that fixed an alarm issue (the CCM now recognizes when the door is open) - not the primary mission, but while I was in there, figured I'd do the job.

I'm 99% sure the reason why it wasn't predictably opening (unlatching) is because of the mechanical nonsense they have going on with the way the door lock actually engages and disengages. The culprit, I believe, is this random plastic piece (yes, mostly all metal in there, except for this random plastic piece that slides to lock the door). You have to separate the two halves, as explained in taligentx's website, to see what I'm describing (this is on the mechanical half, not the plastic electrical housing that taligentx describes). The plastic block/lock mechanism wasn't sliding on it's track properly, and the spring that pushes it had lost some of it's force. I bent the spring and re-lubed the slider. Seems to work, predictably, now. I don't know if I took a pic of that part, but if I did, I'll post it. I read a ton of threads, both here and other sites, of people having to hit their door to get it to open. I'm sure there are other reasons (like the external cable being too tight), but I bet this is one of the least known (and yet very common) causes. I can easily see how it develops over time, and it's quite clear how a jolt to mechanism actually releases the plastic guide about 1-2mm to allow the latch to disengage.
 

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Thanks. I tried my best to compare new units online of each revision, and they look almost identical from the outside, from many angles. I've talked to a VW supplier and they were optimistic it would work, and agreed that the microswitch circuit is likely the major (or only) change. Unless I get lucky and find the one or two people who has tried this, I might be forced to rip everything out and try it myself. No money to be lost, just a ton of aggravation.

EDIT: FYI, part of the reason for me asking is VW doesn't produce the B model (my car's version) anymore. And, no one seems to still have it in stock (OEM VW). If we have an actual VW dealer mechanic on the site, they must run into this situation where they can't offer a new replacement of the old model. Maybe they have to go to rebuilt options if the new revision doesn't work. Hopefully someone will chime in.
Not that this helps you or anyone now, but I'm pretty sure sipes216 was our go-to VW guy. But he doesn't come around here anymore. I don't know of any other members that work at a VW/Audi facility.
 

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Sipes216 is no longer at a dealer, he was spotted working at an AutoZone in Dallas recently.

I put a 2001 B5 driver's front latch into my son's 2001.5 B5.5. Perfect fit, but the remote lock did not work.
 

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Discussion Starter #10
Sipes216 is no longer at a dealer, he was spotted working at an AutoZone in Dallas recently.

I put a 2001 B5 driver's front latch into my son's 2001.5 B5.5. Perfect fit, but the remote lock did not work.
Never actually plugged in the 2002 unit to my electronics since I mostly fixed the original unit. But, as mentioned, it worked perfectly installed as a mechanical backup (all handles worked perfectly fine), while I worked on the other unit. I'm pretty sure they are electrically compatible. If the old unit fails again, I'll probably be plugging in the 2002 unit.
 
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