Help needed working through a central locking fault please?

This is the Forum for all your Citroen Technical Questions, Problems or Advice.

Moderator: RichardW

Rhothgar
Donor 2020
Posts: 1376
Joined: 22 Nov 2004, 01:21
x 44

Help needed working through a central locking fault please?

Post by Rhothgar »

I try to understand wiring diagrams I really do but I am thoroughly lost with this one. I will keep information as concise as possible before I start to ramble.

When I lock the XANTIA 5 DOOR SALOON 1.9 TD (XUD9TE) Manual gearbox 5 RPO 6463, the lock button on the nearside rear does not pull down.

I have removed the button and the door panel.

1) If I try to lock the car, the button doesn't move.
2) If it then try to deadlock the car, the door kicks out slightly. It doesn't actually open but it pushes away from the striker plate.
3) If I then open and close the door again to make it is shut properly and then if I manually actuate the internal lock button and then lock the car, it will lock and deadlock and unlock fine and even relock again without kicking the door out.

I won't say at this point what I have tested electrically as it I cannot get the lock to actuate with a 12V supply directly to it. With the lock removed, I can clearly feel it actuating.

The issue appears to be whatever actuates the internal lock button is not actuating on signal or use of key. Perhaps it is an internal fault with the actuator?

Reading other threads, it appears Givemeabreak is the resident electronics expert.

I have factory manual diagrams if necessary. They mean little to me but we'll not go there just yet. Even with the deadlocking principles factory manual, I'm still lost as to what, if anything, I should be testing anything electrically.

Fingers crossed someone will know what I should do to rectify.
User avatar
ksanturion10
Posts: 229
Joined: 14 Oct 2018, 21:59
x 18

Re: Help needed working through a central locking fault please?

Post by ksanturion10 »

Have similar problem with mine. Haven't made a research of the real cause, but the door has some dents over it and I suspect mechanical missalignment with the locking collar bolted over the body?
Sharkie
Posts: 29
Joined: 26 Jan 2020, 21:59
x 1

Re: Help needed working through a central locking fault please?

Post by Sharkie »

Contact issue in position sensor would be my first guess. Disconnect it and hard lock the door.
Rhothgar
Donor 2020
Posts: 1376
Joined: 22 Nov 2004, 01:21
x 44

Re: Help needed working through a central locking fault please?

Post by Rhothgar »

When you say contact issue in position sensor, do you mean within the actual door lock actuator?

As I've had little reaction to my question, I am probably going to strip the lock completely and re-rivet it. I am guessing it might just be an issue internally with the lock itself because the lever isn't being moved. When locking with the internal lock button, it doesn't feel stiff.

Hopefully, I won't end up destroying the lock in stripping it down. They're not meant to be 'serviced'...
Sharkie
Posts: 29
Joined: 26 Jan 2020, 21:59
x 1

Re: Help needed working through a central locking fault please?

Post by Sharkie »

It knows if it's locked either by position sensor that gets dirty, or by sensing motor current. Front ones have sensors of some kind as the thing unlocks if you wiggle the connector around and also senses that you turn it by key. Not so sure about rear ones. Might just sense motor current.
Rhothgar
Donor 2020
Posts: 1376
Joined: 22 Nov 2004, 01:21
x 44

Re: Help needed working through a central locking fault please?

Post by Rhothgar »

I have stripped the rear lock down today and made a video of how they work.

I'm not sure how to upload a video link though.

Also took some photos. It's really quite a complex mechanism inside.

There are two micro switches. One with 3 wires and has Common, Normally Open and Normally Closed switching and the other one is simply 2 wires which showed continuity and was therefore clearly working as was the 3 wire microswitch.

I measured some voltages but didn't have my deadlocking principle manual with me so cannot recall what voltages I got where. Obviously, it's a little more complex than that but I have sat down with the manual tonight and worked out which pins receive what signal at what point ie locking, deadlocking or unlocking.

The only thing I don't know is whether the signal should always be battery voltage or 5 volts for the 2 wire switch. I know I measured 4.7 volts and around 11.8 volts across different terminals. Now I know what signal goes where, I can try and test to see if it's the wiring or the mechanism.

My thoughts now extend to this:-

It's either going to be a wiring issue outside of the actuator between the 5 pin brown connector and the first splice as the earth is shared with other components which are working or,

it is a mechanical issue internally caused by wear and tear. It is hard to tell if the rod linkage cam is worn. It certainly doesn't look it. The plastic sliders inside are the more likely culprits but it's hard to know what they are exactly supposed to do. With my newfound understanding of the wiring, I should be able to decipher what is going wrong.

I am going to strip out the offside rear lock and substitute it. If that works then it can only be an internal mechanical problem!
User avatar
ksanturion10
Posts: 229
Joined: 14 Oct 2018, 21:59
x 18

Re: Help needed working through a central locking fault please?

Post by ksanturion10 »

Hi, nice that you made some pictures, can you post them?

With properly shut all doors, when locking with my key, it locks all except the N/S rear door (like your case), with following unlock and second locking, then all doors gets locked. Also the lock button in question seems to not go down as much as the others, when all are locking. As I have already discarded the misalignment idea, there must be something related to the button itself. Maybe the lever is moving inside the plastic holder, thus changing its end position relative to the button end, and hence missing to activate some of the end switches?

There is a topic in "handy tips and..." about a repair of such lock button, which means they are prone to fail. What do you think?

BR
Martin
Rhothgar
Donor 2020
Posts: 1376
Joined: 22 Nov 2004, 01:21
x 44

Re: Help needed working through a central locking fault please?

Post by Rhothgar »

Hi Martin

If you remove your plastic internal button, that may resolve your issue. Does that then ensure the lock works everytime? In my case, everything is stripped down so no lock buton or door panel at the moment.

Image
My deduction of what goes where according to factory manual

Image
Plastic carrier, which looks broken but isn't. This allows the linkage which actuates the internal lock button to be engaged or disengaged according to whether the car is deadlocked or not.

Image
Photo of one of the internal switches

Image
Reverse of switch showing whether it is normally open or normally closed.

Image
Photo of internals with crossbar removed so you can see worm gear which shuttles the internal button linkage backwards and forwards and probably engages with other things.

Image
Nib which engages the internal lock button is halfway down on the left hand side. It engages with the hole in the linkage on the left hand side halfway down of photo below.

Image
Internal view of linkages. There is another switch below the right hand linkage about a third of the way down from the top of the photos below the travelling plastic carrier.
User avatar
ksanturion10
Posts: 229
Joined: 14 Oct 2018, 21:59
x 18

Re: Help needed working through a central locking fault please?

Post by ksanturion10 »

Thanks very much for the pics!

I thought, that the inside of the lock is more scary, than it really is :). Definitely will try to remove it as I can hear it strugling every time, when locking the doors :D. I think yours would like some regreasing of the worm drive mechanism, probably mine too - think to use PTFE + copper grease or something similar.

Those red circular parts at the end I think are related to the "dead locking" and can be operated directly with the door opened. But have to see again the user manual, which is in the car. Actually not really sure what is the difference between locking and "dead locking"?

Red your writings, but I need to have the mechanism with me so I can see how things are connected, and then probably to give my view of the innerworkings.

Will report back my findings, when I manage to tackle it.

BR
Martin
User avatar
xantia_v6
Forum Admin Team
Posts: 7908
Joined: 09 Nov 2005, 23:03
x 512

Re: Help needed working through a central locking fault please?

Post by xantia_v6 »

Just be aware that all UK market Xantias had deadlocking (part of the Thatcham rip-off), but this is not true for all markets, e.g. deadlocking was not fitted to French-market cars. The locks and wiring would be simpler without deadlocking.
User avatar
ksanturion10
Posts: 229
Joined: 14 Oct 2018, 21:59
x 18

Re: Help needed working through a central locking fault please?

Post by ksanturion10 »

Rhothgar wrote:
04 Feb 2020, 10:03
If you remove your plastic internal button, that may resolve your issue. Does that then ensure the lock works everytime? In my case, everything is stripped down so no lock buton or door panel at the moment.
Today I only managed to discover another strange thing, after cleaning it from the snow, locked it with my key and again all were locked except the n/s/r. This time I opened and shut it back more harder than usual, unlocked, and all the doors locked back automatically, so I guess there is something sticking into the mechanism or somewhere around the button's guide.

I had a look at the wirings ;), and I think the ECU should be able to change the polarity of the driving motor, no matter the position of left switch into the diagram. Which one is this from your pictures, the white one or the "hidden one". There is also a button to the right of the motor into the diagram. Don't know which is which.
Have you tried measuring the motor?
ALso, but I think you've mentioned this already, changing between the rear locks (if it is possible) and see what happens. Or checking what voltages arrive at the rear right connector and comparing them onto the left one - but this would mean stripping down also the right door :(
Rhothgar
Donor 2020
Posts: 1376
Joined: 22 Nov 2004, 01:21
x 44

Re: Help needed working through a central locking fault please?

Post by Rhothgar »

Sounds more like dodgy wiring. One place to check is inside the doorshut. I've not checked mine yet but that is where they normally go. I know they do on the Mk. 2 Xantia. Not so sure how the Mk.1 is.

The white switch is the one that controls the locking, unlocking and perhaps deadlocking (though unsure on deadlocking). On the white switch you will see a tiny black bobble, that is the switch. Not sure what the hidden switch does.

Resistance on the motor was fairly low. Can't remember the Ohms now. I am going to strip the other rear door. It is the only way to diagnose without wasting time stripping wiring out of the door and stripping back interior. It's the lesser of two evils for me. I can substitute nearside for offside and offside for nearside. This will confirm whether nearside lock is faulty. Strange on it is also your nearside rear too. May be a common problem.