Hi all:
I have lost the B+ voltage for the central locking system. (Fuse is OK). The electrical diagram shows the central point for B+ distribution as X48F. The legend states it is located @ the right rear door sill area. I have taken just about everything in the area out, but cannot find this distribution point. The problem must be wire related, since the other circuits running of the same the fuse are OK.
I tried to chase the + wires, but they go into a channel under the passenger side seat (impossible to get hand in there).
Does anyone know where this distribution point is?

PS. All grounds tested and good.

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1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

We have had the problem at least once. I wasn't the one who found it but I think we removed the seats and some carpeting. The main reason I am replying is that the question has come up before and the point was found. I don't remember who it was but you may find it in the archives. He gave a good description.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

I could swear that there was a final answer but here is one thread: Central Locking Twilight Zone

You might use this thread to continue the search. There may be a separate "fix" post.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

The fix is here
Acccess Hinges on Rear of Front Seats?

Well, now I know what awaits tomorrow:
Remove the passenger's side seat, carpet, and get to that tunnel.

I did not use the right terms on my previous search.

I can never stop mentioning how valuable this forum, and the members in it are.

Thanks again.

PS. I will follow up with what I find tomorrow

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1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

Mission accomplished.
5 wires (B+) were connected in a pigtail, which was very corroded (the green dusty stuff). I touched the pigtail and all wires just fell off from it.
I stripped them, joined them together and pigtailed them again, this time I used a special crimp from my toolbox.

Central locking system works like a charm now.

I had to remove the passenger's side seat and lift the carpet. I took some pictures which will be posted soon.

__________________
1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

Some pictures:

__________________
1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

This has happened to me before, sometimes the pictures do not upload.

Attached Thumbnails

 

__________________
1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

Test

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1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

Location of wires, as reference use the red release for rear seat cushion:

Attached Thumbnails

 

__________________
1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

And here is the inside of the pigtail, the resolution sucks, but the green inside is obvious:

Attached Thumbnails

 

__________________
1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

That's good news! Glad you found that issue....maybe I should check mine while my back seat is still loose

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'87 300E | 2.6 engine
Artic White - Navy blue interior, chrome rims, very clean and sharp!
91 300E
89 300E


The rest of my collection are just cars and trucks...no more "automobiles"...

87-300E_in_NC,
Thanks again for allowing me to test my vacuum pump in your car.

Your system is working fine, but since the seat is off, I would check it.
Right now my back is killing me.

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1999 Porsche 996 Carrera Convertible
1994 420E - SOLD
1986 300E - SOLD, what a car
609 Certified

Well....thanks for the pictures....having the same problems. Will check that B+ connection this week. Couldn't get the locks to cycle yesterday....this morning they worked. Definately a bad connection somewhere. I thought the pump had died.

Reviving this old thread to post some additional pictures and information as I just went through this job myself.

According to the wiring diagrams, I think these are the Z splices referenced in the "Electric Wiring Diagrams of Central Locking Systems" file and/or the X48F + Z82/6 splices documented in the "Central Locking System 146/1" diagram that shows power, signaling and phonemic circuits.

As previously documented, it is located under the floor ~12 inches in front of the rear right seat. If you aren't getting full voltage to the door lock pump, check the 3 Z splices. My problem was with the Red/White splice but since i was there I went ahead and redid the two ground splices as well.

To get the carpet out of the way:
1. Remove the right rear seat bottom (via the red lever) and the plastic bits that surround the seat mount posts
2. Move the front seat as far forward as possible
3. Remove the plastic door sill plate
4. Unbolt the rear sear belt latch (to get the carpet further out of the way)
5. Unbolt the front seat belt from the floor (this makes it easier to complete the next step and it also allows you to pull the carpet back a bit more.)
6. Remove the B pillar trim that meets the carpet

When I pulled the carpet back there was moisture left over from a sunroof drain tube leak I fixed last month. The drain tube shrunk and pulled back into the A pillar. This causes the sunroof to drain right into the floor of the car.

These pictures were taken after I opened up the wiring channel and removed the old electrical tape that was wrapped around all three splices.

Attached Thumbnails