'94 R129 - immobile passenger seat & central locking

[Dec]

When the key blade is turned in the passenger door lock, will the door pin raise and lower?

When you press the window switch to open a window, a relay is energise to raise the window, or, to close the window, another relay is energise, this all happens in the roof control module as discussed in the video below, perhaps the window problem is within this unit.

See also… https://www.google.ie/search?q=1298...-Q4KHQDaA4cQ_AUIBygB&biw=1285&bih=870#imgrc=_

https://www.youtube.com/watch?v=081X0Fxe9us

[YOUTUBE]081X0Fxe9us[/YOUTUBE]

Dec

 

[E55BOF]

Thanks Dec. There are no door pins, just the switch on each door to lock and unlock the central locking. The one on the passenger door does not move when the key operates the lock on that door.

I rather think my pre-facelift car does not have the window drop feature at all.

 

[Dec]

It may be worth looking at the door lock barrel to see if anything is amiss, the spring in the below picture can become dislodges and cause the rod not to turn fully in unison with the key blade when it is turned. Not sure if your lock will be exactly the same but worth a look.
Separating IR door modules from door handles - Page 2 - Mercedes-Benz Forum

Dec

 

[E55BOF]

The plot thins...

The driver's door lock functions as it should as a mechanical lock, and activates the central locking.

The boot lock functions as it should as a mechanical lock, but does not activate the central locking.

The passenger door lock does not activate the central locking, and does not function as a mechanical lock, but when I turn the key fully anti-clockwise in it, I can hear a click/clunk within the door.

The central locking switches inside the car both operate the central locking normally.

I'm coming to believe there are two faults here; a mechanical fault with the passenger door lock, and a non-mechanical fault with either the central locking ECU, or its electrical input connections from the boot and and passenger door locks. Does anybody disagree?

 

[RichardF]

I would suggest a mechanical problem with the passenger door lock, and micro switches on passenger door+boot. Your code reader should give you some more info.

 

[E55BOF]

Can't say for the passenger door lock, but the boot lock looks like an awkward b*****d to remove - I have the trim off, but some linkage dismantling will be needed by the look of it.

I should also have added, the boot mechanical lock does not function when the central locking is locked.

 

[RichardF]

Careful with the boot. Getting it opened again once dismantled can be nightmare AIUI.

 

[E55BOF]

Thanks for the tip. I think I'll take the locking loop off the boot lid, then it can't lock at all until I'm happy with the reassembled lock and linkage.

Looking at the Gen-In info, the only central locking pin is 31, and that is only for "remote central locking"; is it all the same unit, do you know? I don't use the remote central locking, because the key fob is U/S.

 

[E55BOF]

And the plot thins a little further...

I checked the connector at the central locking unit, by the way; all terminals nice and clean.

There's nothing amiss with the boot lock (very easy job to remove/replace, by the way, provided one reassembles the linkage correctly). It has a three-pin electrical connection on the vacuum body, which may well have a microswitch on the inside, but there is no actual electrical connection to it, and no loose connector and cable flapping around in the area. The only electrical connection in the area is to the infra-red locking sensor below the key lock.

Ergo, the boot lock is not meant to operate the central locking on my car, and that is how it left the factory. The problem, then, is with the lock in the passenger door.

Getting there...

 

[RichardF]

That's interesting, my boot lock behaves the same (95my).

I'd always assumed something was wrong. It hadn't bothered me enough to investigate, I don't need to operate C/L from the boot and quite liked the fact it doesn't.

Central locking locks and unlocks the boot, boot key operates boot, but boot key doesn't operate central locking.

Thanks for investigating, it saves me the trouble.

 

[JCW1]

It's good that you are happy that your boot doesn't activate the central locking but for the 93MY the handbook suggests it should and on my car it does. Maybe this 'feature' was deleted for later cars.

I have to say, I could live without it!!!

What mine does do, which I guess is linked, is lock the boot and the petrol filler flap when the engine is started. However, just to make life interesting, it only does it sometimes. This feature, I could definitely live without.

 

[RichardF]

Interesting. The other thing mine does (mentioned in an amendment to the owners manual) but not common with other MY's. The alarm is only set on using the remote, not the key. Quite useful actually.

Not heard of the boot/fuel flap locking thing. I can understand why, plenty of cars do it. Years ago you used to see taxis with a key on a bit of string left in the boot lock. Irritating.

 

[RichardF]

Take a look @ this


http://www.benzworld.org/forums/r12...-diagra-engine-m104-3-2-a-2.html#post13972969

NEXEDGE StarFinder

 

[E55BOF]

Now that looks interesting. I'll see what's on the workshop manual disc I've ordered, and if it's not what I want, I'll try the NEXEDGE stuff.

 

[JCW1]

Interesting. The other thing mine does (mentioned in an amendment to the owners manual) but not common with other MY's. The alarm is only set on using the remote, not the key. Quite useful actually.

Now that is a useful feature. My alarm goes off intermittently so I have to disconnect the battery and lock manually, to avoid upsetting the neighbours

 

[E55BOF]

It may be worth looking at the door lock barrel to see if anything is amiss, the spring in the below picture can become dislodges and cause the rod not to turn fully in unison with the key blade when it is turned. Not sure if your lock will be exactly the same but worth a look.
Separating IR door modules from door handles - Page 2 - Mercedes-Benz Forum

Dec

Thanks Dec. Your picture was useful. There's no spring on mine, but it's similar otherwise. The 'door' end of the long rod is ball-jointed in one plane, and the end fits into a slot on the locking assembly to operate it. Some f**k-witted grease monkey had been inside the door and had the lock unit out, and when he put it back, managed not to get the long rod into the slot... The clunk/click I was hearing was the rod flopping uselessly about as the key turned. Reassembled correctly, it functions as intended.

Probably the same bozo had: broken most of the trim clips, replacing two with self-tappers through the backing into holes drilled in the door; thrown away the door membrane; replaced the 10mm bolt inside the door pocket with a self-tapping bolt of the same size head.

Getting (a bit more) there...

 

[jonnyboy]

Shows the dangers of people doing things they aren't up to - but you're getting there a bit.
See you tonight Dennis

 

[E55BOF]

Looks like a white and brown wire is a live feed from the controller to the switch pack. It should be 5v with the ignition on. You'll also find a brown earth wire.

Not quite as on mine. The wires are coloured white/brown, blue, white/yellow, white/red, white/green and brown. The brown is indeed earthed, but there is a 5V supply (ignition on) to the white/red and white/green wires.

With the door switch pack on the bench, continuity varies between pins as I move the switches.

By chance, I have a spare door switch pack which came in a box of bits I bought. Plugged in, that does not move the seat either.

I don't think it's the switch pack, or the wiring to it. Next stop, the seat controller. Is there one for each seat, or does one do both, and if so, which seat base is it in, does anybody know?

 

[Doodle]

If I recall correctly, it's one each, under the respective seat.

 

[RichardF]

I'm away @ the moment so can't check WIS. I thought it was only one, but my memory isn't perfect.

The seat base comes out easily enough to check though. At the weekend I'll take a look @ the diag info.