Just to be clear, sounds like you agree that the door latch is the most likely source of the problems, correct? In post #1 to this thread the OP identifies that if the window doesn't drop upon opening the door its most likely a microswitch in the latch and it seems likely that the latch acting wonky is the source of the various locking issues and error codes.

On the bright side, this seems like an incredibly detailed thread and source of information about acquiring the proper latch replacement, and its my passenger door so I won't have to deal with getting the key latch shaft aligned during the re-install.

Thanks for your feedback and for everyone contributing to this thread and the detailed information included (it at least gives me the confidence that I can perform this operation).

Thanks for

Yes, in my experience you need indeed a new doorlock to get rid of the double beep, code 59 and LED being lit.

I understood your pass. window drops but not enough. Then it's not an issue with microswitches.
If they don't move at all then it's a microswitch.

Ok great thanks, and even if it is the mircroswitches those will be in the new door latch I purchase/install, correct?

The exterior handle microswitch will be included with the new latch. Interior handle microswitch is a separate part.

FYI for whoever tackles this job next. On my 2000 C2 cab, the VW part referenced earlier did NOT function correctly, and it was a hilarious fail with the vehicle repeatedly failing to remote lock and setting off the alarm every time I tried to open the door. The door would lock manually but no remote functions worked and the key-in-door cabrio trick did not work either. Caveat is that this was an Amazon part not VW OEM.

I went for the URO part, so far it is working flawlessly and corrected my double-beep issue.

Thanks Sublm8 for this response. Odd thing is it was really nice earlier in the week so I was driving with the top down and for that day everything corrected itself oddly. Central locking system light went off, the windows worked correctly from both inside/outside, the remote alarm system worked properly again. Then the next back to the same problems. But my windows always work fine from the center console controls and when the problems start both the interior handle and exterior handle have the lack of window drop problem. It doesn't seem likely to me that both of those microswitches would go simultaneously so I'm betting its the latch that's causing these problems. I plan on buying the URO latch. Can I ask where you purchased and $$?

Pelican, $150 shipped.

Did my passenger door latch today. Weird that you can buy the driver's side P part for $150 (that has the key mechanism) and the cheapest I could find the passenger side P part was $524 (plus shipping). Glad I used the OEM P part and thanks for the good advice on that from this thread. The new door latch solved all my problems with the central locking system and the windows not dropping when using the inside and outside door handles. I took my time and it was about three hours thanks to this GREAT DYI!

Faulty wire? Stumped.
 

Hi all - wondering if you can help me trouble shoot this curious behavior;

when my passenger side door is unlocked the window drops 1/3rd of an inch, when it’s locked the window goes back up to the right position. It does this regardless of whether the door is open or closed.

the window does not drop further by lifting the door handle inside or outside the car. And it does not go back up when I release the handle.

when I do the reset procedure the window goes all the way up and then drops.

The lock button inside the car works a single time if I clear all codes. And then does not do anything after that- no light no action.

I can lock and unlock the car just fine by pressing the button on the remote or using the key. No single or double beep. PIWIS shows the door being ‘open’ regardless of whether it is locked or unlocked, open or closed.

I have changed the lock twice and the regulator motor once and the behavior is exactly the same. I have checked the part numbers with Porsche and they have confirmed them. I disassembled one lock and its micro switch was perfect.

the only thing I can think of is that there is a wire that goes from the micro switch to the M535(?) control unit that tells the car the door is open or closed is cut somewhere. But which one is it? How could I test that?

Appreciate any ideas

Stumped
 

Closest wiring diagram I found is here
https://rennkit.com/wp-content/uploa...iring_2002.pdf

I believe there are microswitches on the outer door handle mechanism as well. Looks like you've tried everything else.

Stumped continued
 

So here’s what I’ve done. Firstly here are all the micro switches. The ones in the latch do something so work. The door handle micro switch is brand new. I assume that works.
https://cimg6.ibsrv.net/gimg/rennlis...3dd3f622c.jpeg

I made a little harness so I could press my remote button and activate the door lock motor:

https://cimg0.ibsrv.net/gimg/rennlis...77d933647.jpeg

I ran PIWIS and cleared these codes:

https://cimg8.ibsrv.net/gimg/rennlis...4ad6830eb.jpeg


I then tested every combination. The external door handle switch did absolutely nothing in any combination so I made no notes on that.
https://cimg5.ibsrv.net/gimg/rennlis...bdf8c77b9.jpeg


Next post I will share my notes

Stumped notes
 

Notes -

When I manually ‘lock’ the door by moving the harness to the lock position PIWIS sees the door as both locked and closed.

In the lock position if I then press the microswitch to simulate the door being opened, the window drops correctly, the interior lights come on and if I release it the windows returns to the correct position and the lights go out. It all behaves correctly so long as the door is manually set to the lock position:

https://cimg5.ibsrv.net/gimg/rennlis...3dac720d02.jpg

It is like the door lock is sending one extra signal when it should not be. It’s communicating that the door is locked or unlocked AND it’s communicating that the door is open when the car is unlocked.

Now the other issue I have is that the lock button inside the car works once after codes are cleared and is then disabled. So I can’t ‘close’ the window to its right position whilst driving.

All 3 door locks I’ve tested have the part number 3B183701P. I rechecked pelicanparts and it confirms this is the right part for a 1999 Carrera. Haydon Porsche website says the same.

I can’t see any obvious damage at all to the wires but will clean contacts next. Really I have changed the lock out so many times they should have been scraped clean by now. I have had the drivers seat out last weekend and the M535 module was clean and had no corrosion. The floor showed no signs of ever being damp. I changed out the ignition switch last weekend too.

I’d love some ideas of what to look at next

I've had a similar behaviour with the passenger door on my 996 where the spring on the external handle was sticking, and the handle would stay up even with the door successfully closed and this caused the interior light to stay on and non-normal behaviour

I think if your handle is having no effect on your matrix grid, then this would be where to investigate as it should definitely make a difference

Try having an free roaming micro-switch connected to the external handle micro-switch wires, and then closing this from inside when the door is closed - might help track down the problem

BTW I've changed two locks and one door cable on my 996s so feel your pain...

All the micro switches are free and roaming, I’m wondering if it’s a different door lock part number I need. Drivers side works just fine (although now has some slop) so I might go check what that part number is .. I guess it should be a matching pair to the passenger door but if it’s not that might be it

Just to confirm my message above, I ordered Porsche part #3B1-837-016-P, the right hand (passenger side) door latch for my 2002 996 C4 (and the same part is listed for the 996 and 986 from 1998 to 2004) and it solved all my central locking system and window drop to open problems.

Good luck,