2015, C4 Grand Picasso drivers/passenger seat wiring identification please?

[Davebullock]

Hi everyone,
Can anyone help me with identification of the car to drivers seat/passenger seat wiring identification please?
I have a pair of front seats that I am trying to transplant into a campervan conversion and can't find any information about wire identification.
The seats seem to have an electronic control box within each seat that the various seat control switches go to. These control things like 'lumbar support' adjustment/massage function, foot rest extension (passenger seat) etc.
However the connector that connects the seat to the car has wires for things like airbag detonation, seatbelt insertion, seat pad switch, too....
It would be great if I can get all the electronic controls within the seat working using the built in electronics but I can't without knowing the seat to car connections/wire identification.
There doesn't seem to be a Haynes manual out yet for this vehicle so am totally stuck.
Does anyone on this forum have this information they would kindly impart to me for my project please?
Thanks in anticipation
Dave

[GiveMeABreak]

Are you saying you are converting a C4 Picasso into a campervan, or trying to put C4 Picasso seats into another vehicle?

If this is a transplant from one Picasso to another, I think you'll also have other problems because it's not just the seats and their internal control units you need to worry about, it will also be the control modules that link to them - usually located in the driver's door. These are specific modules and are different depending on trim levels at factory - soi you cant just plug these in on a lower spec. vehicle and expect them to work. The wiring from the seat belt pretensioners and airbags has to be correctly wired into the Airbag ECU too..

Once I understand what it is you are trying to do (from what vehicle to what vehicle) it might help further,. Also in either case I will need a VIN number - from both cars if possible or the registration number from the donor vehicle if you don't have the VIN.

[Davebullock]

HI,
I am transplanting the front seats from a C4 Grand picasso into a Mercedes High roof long wheelbase campervan that my son and I are converting.
Tracing out all the wires in the seat to car milti-plug we have identified most of the wires like airbag detonator/ seatbelt insertion detector etc.
However we have a few wires left that we can't be sure what they do. There are a couple of thick wires that are clearly power and ground that go directly to the in-seat electronic module but the colours aren't red and black (of course) so we really need to find a chart that explains :-
a) What colour coding Citroen use for their wiring?
b) What the pinout of a 2015 Grand Picasso seat connector is?
c) Is the seat connected to a CAN/LAN (or similar) bus or is the seat just standalone and dc operated?
Regarding colour codes within the seats ..... Citroen seem to have had a bad wiring day as green wires turn into blue where there are official junctions in the seat looms.
I have had to remove all the loom binding tape to discover this anomaly .... completely crazy!
I can fairly easily convert the seats with relays to operate the internal 'works' but if it is possible to use the original electronics it would be a much neater solution.
Sadly I don't have the VIN number of the donor car.
Thanks in anticipation
Dave

[GiveMeABreak]

Non starter I think. Citroen don’t use specific colours for specific wiring. Further there are interconnections throughout where this happens.

Secondly it will be full CAN multiplexing using differing high speed low speed comfort and LIN networks. so without a compatible BSI and all the fuse box modules to interface with the seat ECU and possible door control modules, I can’t see it working as intended.

My other concern is the airbags and pretensioners that again are designed to work with a specific airbag ECU used by PSA.

Most equipment on PSA vehicles is fully multiplexed requiring a specific BSI and electrical architecture that will be different from Mercedes.

Without the correct data signals and control commands being sent to and from the BSI to the seat ECU and / or door control module, it won't operate. So you would have to bypass the ECU completely and wire up separately controlled switches to every button to a power source for a chance of them working.....

So you won't have airbags in the seats and pretensioners of course as they also relay on specific commands to determine whether they operate or not depending on impact severity and location and of course at what level they trigger.

There are hundreds of wiring diagrams, but without a VIN I cannot get a specific one. What year and exact model is the donor Picasso?

[Davebullock]

HI Marc,
Thanks for your thoughts.
Yes I wondered if the seat ECU was in digital contact with the rest of the donor car. In the Mercedes Sprinter there is'nt that complexity of control signals.
The seat belt pre tensioners are in the door pillars, the seat belt catches are just DC switches. The airbags are built into the van and there were NO airbags in the seats. and the 'seat occupied' sensor is also a straight push switch.
So that rules out needing to reconnect nearly all the interconnections between the C4 seat and the outside world. (there's nothing to connect them to!)
I have eliminated/identified all the wires except the two thick (power?) wires and two other thin wires.
Of the thick wires...one goes to the ground plane on the seat ECU and one goes to the anodes of two SMD diodes (so probally +12V even though it's a green wire....sigh).
All the internal wires from all the switches go the the seat ECU. So I am left with two unidentifiable thin wires that go out through the seat-to-car plug that are puzzling me.
All other wires go to things that are identified and irrelevant in my situation. UNLESS, the two unidentified wires are a CAN/LAN bus that feed a remote car based ECU that then monitors all the seat sensors before it lets the seat ECU operate. (sounds like this is the case?)
Powering the seat ECU does nothing none of the seat controls operate.
All I know at the moment is that the seats were from a 2015 C4 grand Picasso
I know what all the internal wires do and can (as you say) utilise these wires with new relays to get the 'works' operational. Though NOT the lumbar massage feature
Thanks for your time.... you are a gentleman.
Dave

[Davebullock]

OK so I have extra information about the donor car though sadly no VIN number
The care was:-
Citroen C4 Grand Picasso Exclusive+ Bluehdi EAT6 1560 Diesel
Does this make any sense or even help?
Thanks.....
Dave

[GiveMeABreak]

I’ll have a lol Dave based on this info, I’ll have to be creative on the rest, but if I go for a fully functional seat I may be able to assist. Yes these are digital systems and also be aware that the driver ECU module in the seat MAY also interact with passenger one via CAN.

I’ll Rory back shortly.

[GiveMeABreak]

I'm not sure how much help this will be as fro the C4 Picasso from 2014 on there were another couple of types of electronic architecture added, each being different, and to add to matters, the seats had different modules and control mechanisms depending on the trim level - there were a multitude of options / electric / manual, with and without this feature that feature etc., etc., .

So I have put these three diagrams up each showing some of the components - but all rely on the various ECUs to authorise and command the operations and to obtain the feedback from the various incorporated sensors.

Driver Electric Seat



Leg Rest



Massaging Seat

[Paul-R]

I’ll have a lol Dave ...

I’ll Rory back shortly.

Voice identification, autocorrect or both Marc?

[GiveMeABreak]

Oh Hell, I usually have that issue with Siri, but can’t blame her this time, just this damned stupid autocorrect! Well spotted!

[Davebullock]

Wow, Many thanks for digging out the schematics, you are a star!
I will print them out and see if we can make a comparison to the seats we have. It looks though like you say getting the seats woring electronically will be a non starter as there are too many expected electronic interactions going on between the seats and the car.
Thank you for all your help in clarifying the situation, it is greatly appreciated.
All the best
Dave

[RichardW]

Annoyingly those diagrams don't give the pin out of the actual connector under the seat (I wonder if the little white box indicates where the connector is?), so you will need to trace back to the ECU or other unit to find the wires (although they may be numbered (in small print) at the connector.

My take on them:

Leg rest - there is no ECU and the only connection to the BSI is to power up the relay, so this should work if just powered (two pins!) and earthed.

Electric seat - 3 wires to the BSI, one of which is a power feed. Presume the main feed comes via F12 in 'BFH3' (whatever that is). I would guess the other 2 wires are datacoms with the BSI - I'd be surprised if it wouldn't work without these, they will just be for allowing interogation of the ECU, flagging faults (and possible transmitting which key is in use so that the seat can revert to a memorised position if this was installed on the original car - don't even know if it was available!).

Massage / lumbar function (assume this is fitted separately to the electric movement - do you have the buttons on the front inside corner of the seats?) - again 3 wires to the BSI, but this time one is an earth. Other 2 presumably the same data comms connection as for the electric seats.

[Coldo]

Hi , I was wondering whether you managed to get the seats wired into your camper , I’m in the process of doing this also to a fiat ducato , same platform to the Citroen relay vans , I was hoping that I could get them all wired in