406 @#$%&* Door locks !

[Armidillo]

I know other people have had problems with these, so hope some of you have suggestions:

It’s a D9 (2001, not CANBUS) and it’s an SV (shouldn’t be relevant).

The problem is that when I press the remote button, all door locks (& the boot lock) make locking noises, then immediately unlock again!! It all worked perfectly when we bought the car a couple of years ago!

The handbook tells me that “If one of the front doors is open, the central locking does not work”. So I shouldn’t need to test the back doors? What about the boot? Is it definitely not monitored?

So it seems the system thinks one of the front doors is open, no matter how carefully I close them. So what is the mechanism that decides if a door is open – it appears to be different to the device that turns the lights off when I close the door, as this appears to be working normally...

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Cheers

Alec

[Peter C]

My 2001 D9 406 also does that if one of the back doors isn't closed.

[Peter C]

Will still lock okay with the boot lid open.

[Armidillo]

Thanks Peter - sounds like I'd better not ignore the back doors then!

Can any one explain where the sensor is that 'decides' whether a door is closed or not? It doesn't have a little button in the door frame like earlier models...

Cheers

Alec

[TrinityJayOne]

The boot thing is probably a common Peugeot trait, my 306 has the same behaviour.

[driven]

My 206 had the same problem, ended up changing the lock mechanism on the door.
No use getting second hand ones as they will fail as well

[Roland]

Thanks Peter - sounds like I'd better not ignore the back doors then!

Can any one explain where the sensor is that 'decides' whether a door is closed or not? It doesn't have a little button in the door frame like earlier models...

Cheers

Alec

I always assumed the system was linked to the interior light switches mounted somewhere around the door frame.

[Peter C]

I always assumed the system was linked to the interior light switches mounted somewhere around the door frame.

I'm not able to find the light switches anywhere on the door or door frame so maybe they are part of the locking mechanism.

[Armidillo]

I don't know why the lights would use a different sensor to decide when the door is closed, but the cabin lights know when the doors are closed, and switch off. I agree with Peter, it must be in the door lock mechanism for the more recent models.

[Peter C]

I suppose we all look for a door frame mounted switch because, traditionally, that's what's always been used.

Nowadays, if you need to detect whether or not the doors are closed, you may as well use that to switch on and off the cabin lights. Simpler and cheaper to make.

[addo]

All four door locks have a "make to ground" contact that is activated when the lock is released (door opened). This signals the light and locking controllers to do their stuff (separate boxes in D8 406, Texton box in later 406, then BSI).

When the car plays up, disconnecting the harness at the door plug (not the lock) is possibly your first port of call.

[Armidillo]

I have an extra piece of evidence:

If I lock the passenger door with the key, it behaves exactly the same as when I press the remote.

OTOH, if I lock the driver's door, only the driver's door locks - nothing else reacts at all. That seems to point to the problem being in the driver's door.

I didn't realise there was a door plug - although after a moment's thought it's pretty obvious that they must exist.

From the diagram in Service Box I assume the plug is in the car body - not the door. Do I have to remove all that trim to get at it/them??

The harness is NFP, and even if it was available, it would be over $400!!! By comparison the door lock is cheap & available (but probably not the problem ). In fact surely you'd only replace the harness if the old one was melted (mine most certainly is not) - otherwise it should be repairable (if it is the problem).

Cheers

Alec

[addo]

Both front doors have an additional telltale switch in the lock, that commands the locking controller. It supplies an earth to one of two possible wires (Lock and Unlock).

In your case, and with this additional info - I'd suggest unplugging the driver's door lock at the lock itself, and seeing if that resolves the ghosting issue. You will have to manually lock the driver's door, and use the front passenger door or your remote, to lock the rest.

[dcc236]

It is part of the lock.

Sent from my GT-N7105 using Tapatalk

[Armidillo]

Both front doors have an additional telltale switch in the lock, that commands the locking controller. It supplies an earth to one of two possible wires (Lock and Unlock).

In your case, and with this additional info - I'd suggest unplugging the driver's door lock at the lock itself, and seeing if that resolves the ghosting issue. You will have to manually lock the driver's door, and use the front passenger door or your remote, to lock the rest.

Unplugging driver's door makes no difference to the other doors (& boot) - press remote (or turn key in passenger door) and they all lock, then bounce open.

Have replaced driver's door lock with a known good unit (well - assumed good ) - still makes no difference. Does this mean we are (OK - I am) back to checking the driver's door harness? Didn't bring my multimeter, so won't be doing it tonight...

I had similar problems with Harvey's blue Xantia wagon (passed on to No. 1 son) - in that case I deduced that problem lay in front passenger door lock. Fitted a 2nd hand one from David C. - no further problems! Why can't it be as simple this time

Cheers

Alec

[addo]

Did you buy the known good one from Happy Man?

[Armidillo]

I thought he was a Citroen wrecker? Mine's a genuine Peugeot one - actually brand new, & with correct 6-pin connector. Price would have been acceptable if it had worked .

[addo]

Your car probably has a Texton box for lights and locking if it's not COMM equipped. It must have the later (non Xantia style) door locks though.

[Balki]

I have found lubricating the lock mechanisim with spray lube will fix them, if one is a bit sticky the doors will all unlock again

[WLB]

Do you mean the parts accessible when the door is open or the parts inside the door, when the door trim is removed?

[addo]

The switch is within the lock casing; I presume Balki is talking about getting Servisol or similar contact cleaner/lubricant inside the housing.

Could well be that dust has made the grease sticky.

[Armidillo]

OK - no real progress, but tried a few things.

Quick precis of problem(s) - remote door locking activates all latches, but they instantly spring open again. Using the key on the passenger door gets the same result, while using the key in the driver's door locks that door only - no activation of electric latches.

Replaced driver's door latch mechanism with a brand new one - absolutely no change!

Thanks Balki, but lubricating the latches hasn't helped (yet) - I sprayed WD40 (Repco equivalent) into the visible latching mechanisms.

The driver's door plug has 5 wires (connected via a 6-pin plug). I have done some tests with a multi-meter:

Red 5.?v constant
Green/Yellow strip Earth
Beige c. 12v transient when remote pressed
Yellow c. 12v transient when remote pressed
White Nothing (but not earth)

Have not yet pulled apart passenger door to make comparisons, but thought I would investigate a working system. The working system is actually a Xantia, but the part number for the door latch (9136J6 for driver's door) is the same. I have removed door trim, with only a few pieces of hard plastic breaking .

Now the Xantia has a 9-pin plug, while the Pug is 6 pin. However for earlier models (ORGA prior to 8576 - mine is 7708) Service box lists the 6 pin plug and spade connectors as required "options". Trick must be knowing which wires to use when "downsizing" from 9 to 5 wires .

Ok - findings from Xantia:

1. Disconnecting a door plug does NOT allow remote locking of the remaining doors. With driver's door latch unplugged, it behaves just like 406 ie other doors try to lock but bounce open again. Bridging connectors may mimic door latch, but which ones?

2. Back doors are not monitored - locking still works with door wide open. (Obviously the 406 could be different...)

3. Despite the part numbers being the same, the voltages look very different. Hard rubber shrouding prevents me from knowing which wires connect to which pins, but I found an earth (or 2), one wire delivering c. 3.5 volts, and several giving a constant 9.8 volts. Assuming that the 3.5V is probably doing the same job as the 5.x on the 406, the 406 has no equivalent of the 9.8v wires .

In other words I'm not much wiser - will probably have to remove the trim from the 406 front door and compare voltages on that harness. Unplugging door harness at pillar a) looks difficult, b) would be less obvious which wires are for door lock.

While I had Xantia in bits, tested a "faulty" Xantia door latch that I replaced a couple of years ago - worked perfectly .

So now I have 2 cars partially dismantled, and I have to go out .

Any insights/suggestions gratefully received

Cheers

Alec

[Peter C]

Could the white wire be for the door louspeaker?

[Armidillo]

The wires I've listed above are all from the plug that connects the door latch - so one would expect them all to have a function relating to locking/unlocking.

The door harness as a whole of course contains speaker wires in addition to wiring for adjusting mirrors and operating windows - and of course locking doors. This is one reason I've baulked at unplugging the door harness just before it enters the door - too complicated for my little brain!!

[Peter C]

Delving deep into the harness isn't someothing I'd relish either. On the other hand, it sounds as though that could be your next step. Maybe a broken wire etc.