[Xantia 93] Tailgate lock servo unit

Post by **Darko** » 14 May 2006, 12:30

Hi,

I had some problems with the tailgate lock so I disassembled the thing and figured out that the problem appears to be with the servo unit...

Does anyone here know how is this thing supposed to work? Particulary if the latch is supposed to move freely (it offers no resistance) or should it turn the motor inside when you move it?

Thanks,
Darko

AndersDK · Post by **AndersDK** » 14 May 2006, 12:56

Lock servos are strange creatures - you can freely move the plunger (rod) in/out the unit.
All it does is to shortly apply force moving the latch that locks the door - exactly like a key would do it when you turn it.

To test a lock servo : simply apply +12V & earth to each terminal, and the servo should "fire". Once voltage is removed, the unit is slack again.
Reverse voltage to the unit and the plunger fires (moves) opposite.

Most likely problem you have is chafed cables somewhere on the run to the boot door - especially in the gaiter.

Post by **Darko** » 14 May 2006, 13:08

Hi,

thanks for fast answer!

Well the problem is not that the servo doesn't fire, but that with the servo attached, the lock locks itself every time it is pushed/pressed... I unlocked it, pressed it and the tailgate opened, however it became locked again. Now when I removed the servo, the lock cylinder retains its position and works as it should (except that there is no central locking now, of course)...

Any ideas?

Thanks,
Darko

AndersDK · Post by **AndersDK** » 14 May 2006, 13:15

My best bet is the cable chafing option - can really make you pull your hair

... as then the lock appears to have got a life on its own

wrinklet1 · Post by **wrinklet1** » 16 May 2006, 09:52

Darko,
Have you checked out the lock itself? It has a setting that stops the lock/boot from being unlocked, put the key in and turn to an angle at about /, the key will come out and the boot will not be unlocked until done with the key.
Give the lock a good squirt with wd40 too

Paul

Post by **Darko** » 16 May 2006, 14:33

Hi,

When the servo is "unlocked", the plastic rod goes in, however it comes back out a little bit... So if I manually push the rod into the unit, it comes back about a centimeter like if it was on a spring or something... It is still enough to open the lock once, however the second time (except if open the lock VERY carefully

) the two parts of the lock dont 'catch' themselves anymore and therefore the lock becomes locked again

So if you push the rod into the servo, is it supposed to stay exactly there or is it okay if it moves back a little (like mine does) - to me it appears that is the problem. As I said before, the lock works normally (with the key) if remove the servo...

Thanks,
Darko

samtronic · Post by **samtronic** » 20 May 2006, 14:42

I have more or less the same problem, that the rod in the servo unit is so loose it can move a bit out whith enough vibration (driving, closing the tailgate) and thus lock the tailgate.
This would not be so annoying if I had a plip or the lock in my tailgate worked, but it don't turn with the key inserted.

I have removed and dismantled the servo unit using some force (it is glued/melted together) and I can find nothing mechanically wrong with it; if I apply power the rod moves in or out without problems, but won't stay all the way in - it is pushed a cm or so out by the rubber bellows.
It seems like some sort of grease has been present, but is now dried out. I guess some kind of sticky grease has been used to prevent the rod to move to freely, but is is now gone and the rod can move freely.

Regards,
Søren A.M.

Post by **Darko** » 20 May 2006, 14:53

samtronic:

can you take a photo of the inside of the servo unit (if you have a camera, of course)?

samtronic · Post by **samtronic** » 20 May 2006, 16:35

can you take a photo of the inside of the servo unit (if you have a camera, of course)?

Sure:
out
in
out - different angle

Regards,
Søren A.M.

ghostrider · Post by **ghostrider** » 20 May 2006, 18:41

I had the same problem, it started when the wires developed an internal break where they go into the tailgate, I ran new wires which fixed it for about a week and then it stopped working again. My key operated lock in the tailgate is corroded solid so no chance of working it that way.

When you stand by the tailgate can you hear the servo when you operate the central locking?

Mine made a noise but not the same as the rest of the servos on the other doors. In desparation I fitted the servo off a BX and hey presto it works and has done for about a month. The old one seems fine when you run it from the battery but it does not work on the car.. bizarre

supply voltage seems Ok but it may be a different story under load
________
VAPORIZER AFFILIATE PROGRAM

samtronic · Post by **samtronic** » 20 May 2006, 22:13

Hi again,

the central locking on my car works fine; it's the only way I can lock/unlock the tailgate and it always locks and unlocks the locks.

I have made a modification to my lock servo, and it seems to work great when I test it out of the car.

Here are a couple of pictures:
The modified servo unit
A closeup
Another closeup

The spring I have used can be found near most computers: It is the spring which closes the metal shutter on a 3.5" floppy disk. One end is melted into the rod with a soldering iron, the other end sits in a groove cut in the casing with a knife.
I probably need to secure it a little better, but these first tests looked promising.

A few minutes later:

The spring is now better secured:
One end
The other end
I just melted short pieces of wire into the plastic to keep the spring in place.

Regards,
Søren A.M.

Post by **Darko** » 21 May 2006, 12:55

samtronic: Nice!!

Post your results here after you test it in the car

samtronic · Post by **samtronic** » 21 May 2006, 13:05

I have mounted it in the car again, and it works just fine thus far.

And now I know why the screw holes in the servo unit are painted white

I'll have to use the car for a while to see if the self locking fault reappears or other problems occur.

Regards,
Søren A.M.

Post by **Darko** » 22 May 2006, 19:47

I did the same and it works now!! Thanks!

* Darko hands Søren a virtual beer

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