Ducato central locking

[Robin M]

HELP !!

I have an issue which is causing a lot of unsuccessful head scratching. I have a Burstner motorhome on a Ducato cab/chassis. The central locking system has developed a mind of it's own. Even when the key fob is no-where near the vehicle the locks will suddenly unlock without warning / lock again / unlock / lock again ….............. sometimes for hours at a time. This is accompanied by the overhead cab lights switching on and off in time with the central locking.

My local service facility has never come across this issue before and has honestly told me that solving it would be on a trial and error basis. ( potentially very expensive I think ). Any pointers you could give would be appreciated.

[Labby]

It seems that there  is a Door management control unit  fitted to X250 Ducatos (and maybe X290 ) that is under the dash on the right side (according to a Fiat manual) and maybe this could be the cause of the problem or the multi-plug connection it has on it may need checking .

There is also a signal receiver under the dash that is linked to the central locking and courtesy lights.

[witzend]

On 2/10/2023 at 6:09 PM, Labby said:

It seems that there  is a Door management control unit  fitted to X250 Ducatos (and maybe X290 ) that is under the dash on the right side (according to a Fiat manual) 

Could it be incorporated in the BCM if so its possible to get it serviced. My local fiat dealer priced a replacement at £700 + vat. 

[Labby]

The door control unit appears , in the manual diagrams , to be a separate item from the BCM , not sure about the signal receiver though ,  

[Philjp]

Is this happening when parked at home or at another location?

[Robinhood]

AFAIK, whilst the X/244 Ducato had a separate door lock control unit, with the advent of Canbus in the X/250, the function has been incorporated into the BCM. (there are various people purporting to sell CL control units on eBay, but checks on the part numbers indicate they are anything but). The cab lighting circuit on the X/250/X/290 is closely associated with this function.

Potential diagnosis will thus depend on the particular version of the Ducato the OP's unit is based on.

It would also be interesting to ascertain whether the habitation door has been incorporated into the C/L function by Burstner (because, if it has, and playing the odds, I'd be starting there for diagnosis).  

[Labby]

If it is a X250 series the manual  does  show a separate specific door management control unit , it can be in four possible operating configurations , which can be  identified by a label stuck on the  unit , it has its own fuse , F36 ,  and works in synergy with the BCM .

[Hans]

Just put OBD to it. And x250/290 is the same.

[Robinhood]

I think, from the diagrams, that the CGP (door management control unit) is simply an interface from the BCM to the door locks themselves, and effectively contains only relays (in differing combinations) to provide power to operate the respective locks fitted, and is essentially otherwise "dumb". The logic for locking unlocking (i.e. the signal to the CGP) is provided by the BCM.

Patently, there could be a fault in any of the components involved, but for the symptoms described it is probably less likely in the CGP.

There appears to have been some history of wiring failure to Burstner habitation doors, where these are connected to C/L, which is why I asked the question about that. 

[onecal]

Hi

Have a look at the bottom hinge , You will see an electrical connection wrap, Peel back carefully and you may find a broken wire within . Repair and it may solve your problem We have found this to be a common fault with locking and unlocking in some situations 

Regards