W203 - Memory seats retrofit

[Jim3880]

Hi guys I’m looking for any advice on retrofitting front memory seats into my 2006 W203 C320 CDI.

Currently I have heated + power seats, with only the manual adjustment for physically moving the seat forward and backwards.

I recently purchased a full set of C55 amg interior (including door cards with switches mounted on them) which is in great condition. This interior has the memory facility and additional motors to move the seats forward and backwards.

What I would like to find out is if my current door control modules will be the same as for the memory seats? (I didn’t get the door modules with the seats) Is it possible that my modules just need recoding? (The under seat modules for the C55 seats were included).

I assume that I may need a new wiring loom to accommodate the memory seats. Sadly I didn’t get this from the C55.
Does anyone have any part numbers for the loom(s) I may require?

Any advice or comments would be most welcomed!

Thanks in advance,

Jim

 

[Petrol Pete]

Hi guys I’m looking for any advice on retrofitting front memory seats into my 2006 W203 C320 CDI.

Currently I have heated + power seats, with only the manual adjustment for physically moving the seat forward and backwards.

I recently purchased a full set of C55 amg interior (including door cards with switches mounted on them) which is in great condition. This interior has the memory facility and additional motors to move the seats forward and backwards.

What I would like to find out is if my current door control modules will be the same as for the memory seats? (I didn’t get the door modules with the seats) Is it possible that my modules just need recoding? (The under seat modules for the C55 seats were included).

I assume that I may need a new wiring loom to accommodate the memory seats. Sadly I didn’t get this from the C55.
Does anyone have any part numbers for the loom(s) I may require?

Any advice or comments would be most welcomed!

Thanks in advance,

Jim

Hi can't help you on the seat fitting but may I ask where you purchased the C55 stuff from ? I might ned a few parts. You can PM me if preferred

 

[Hectors Dad]

Hi guys I’m looking for any advice on retrofitting front memory seats into my 2006 W203 C320 CDI.

Currently I have heated + power seats, with only the manual adjustment for physically moving the seat forward and backwards.

I recently purchased a full set of C55 amg interior (including door cards with switches mounted on them) which is in great condition. This interior has the memory facility and additional motors to move the seats forward and backwards.

What I would like to find out is if my current door control modules will be the same as for the memory seats? (I didn’t get the door modules with the seats) Is it possible that my modules just need recoding? (The under seat modules for the C55 seats were included).

I assume that I may need a new wiring loom to accommodate the memory seats. Sadly I didn’t get this from the C55.
Does anyone have any part numbers for the loom(s) I may require?

Any advice or comments would be most welcomed!

Thanks in advance,

Jim

Jim,
I did this retrofit on my facelift 2015 S212 and it took a while as I went the whole 9 yards and did electric steering column and full 275 memory package.
If you just want full electrics without memory then it actually consists of 2 CAN wires (if the W203 has CAN?) on each seat, maybe an updates door control module and a swap of feeds in the rear SAM.
All of this is taken from my S212 so may be different for the W203 but it's a starting point.

 

[Jim3880]

Thanks for your reply. One of my friends recently purchased a w203 with memory seats and I managed to get some photos of the underneath of his seats. It appears he has an additional plug on his wiring loom which goes to each seat, which I do not have on my current factory seats. This must be for the memory / door control switches.
I’m not sure if cars which factory fitted memory seats have a different loom which goes from the door control module to the CAN. If so, this will be too much of a job for me I feel (both fitting and working out the loom part numbers required)
I may just have to swap the C55 cushions onto my current seat frames. I will carry on looking into it and post on here with the outcome!

 

[zipdip]

Yes I think like others before you have found that the looms are different,quiet why car makers do this is crazy,just how much time and money is lost by not having the looms for one or two different builds,when if they paid maybe a very small amount to have one loom fits all,there would be large cost savings,

 

[DSM10000]

Yes I think like others before you have found that the looms are different,quiet why car makers do this is crazy,just how much time and money is lost by not having the looms for one or two different builds,when if they paid maybe a very small amount to have one loom fits all,there would be large cost savings,

If there were such cost savings then manufacturers would do so, the fact that they generally do not is surely an indicator that it is not?

 

[zipdip]

Well the vast amount of looms are made in the far east,South Korea is a big maker of them,the cost of two extra wires and two plugs is minute,and set against the fact that people who order cars with say a heated steering wheel or rear massage seats,find that there orders are delayed because the makers of the looms do the big orders first,and the little orders cost more as they have to spend time setting up for them,but hey many think that car makers like it that way because as the op has found out it is not so easy to add extras to the car he has.

 

[Petrol Pete]

Far more complicated than that.

 

[richard]

As someone who talks to a rather large amount of people about retrofits, many are surprised to find that there is no spare wiring, or that when you have COMAND or Digital Cockpit additional fans are needed etc.

My answers are always as follows:
a) Saving $1 per car on a million cars adds up pretty quickly
b) Mercedes would not waste $$ adding a cooling system for your Digital Cockpit / COMAND if they could avoid it. Without it things will break within the 3 year warranty period or they really wouldn't have bothered to put it in

And if they really want a chat about it, then theres a whole bunch of things that get wired differently depending what options are in the car. The MOST fibre optic network that goes to each device (and the fibre is actually quite expensive), and the FlexRay data network that goes around the parking system and all the driver aids on the newest cars.

R

 

[Petrol Pete]

What Richard said ^^^^^^

 

[KevinH2000]

Did you succeed with this project? I am embarking on a similar project and I would appreciate any guidance you can share.
This link will take you to the information I posted on another forum.

 

[zipdip]

No wiring looms used that are not needed,and so cue the quote of around £2000,not sure if that includes VAT

 

[markjay]

I imagine that extra wiring looms also mean more weight, which these days is a big no-no (due to CO2 and other emissions).

 

[DSM10000]

No wiring looms used that are not needed,and so cue the quote of around £2000,not sure if that includes VAT

The issue being?

 

[Jim3880]

Did you succeed with this project? I am embarking on a similar project and I would appreciate any guidance you can share.
This link will take you to the information I posted on another forum.

In the end I decided it would be too much work for me, tbh I doubt I’d really use the functions often - except for the 1 time a year the MOT tester moves the seat back (I’m not the tallest of people!)
I just swapped the seat cushions over, with the exception of the headrests as I couldn’t work out how to open the headrests as they have the pop forward accident spring etc inside. If anyone can help me with guidance for this it would be much appreciated?
Best of luck with your project, I hope you get it working all ok

 

[Jim3880]

 

[KevinH2000]

Thanks for the reply. I posted updates here.

I should have time to work on this by the weekend. The part of this project I don’t fully understand is the communication between the door and the seat. A moderator on one forum stated the seat is already on the CAN Bus. That would simplify the task if the information is accurate.

 

[Hectors Dad]

Thanks for the reply. I posted updates here.

I should have time to work on this by the weekend. The part of this project I don’t fully understand is the communication between the door and the seat. A moderator on one forum stated the seat is already on the CAN Bus. That would simplify the task if the information is accurate.

The CAN BUS is basically a network that runs throughout the car and is connected to various modules and ECUs. It carries signals that enable activation of various services and / or modules within the car. The memory function for the seat is made possible by the Seat Control Module underneath the seat and it is THIS that needs to be connected to the CAN BUS.

If you already have the seat movement functions on the door panel then your seat is indeed connected to the CAN BUS (or the functions wouldn't work).

This is a stab in the dark without actually seeing the seat but I would guess that you need the new seats with Seat Control Modules underneath that have the memory ability. Door card seat controls that have the memory facility and some coding to enable the car to see the new feature.

Do also be aware that on the S212 (I did the full memory conversion including steering column and mirrors etc on mine) that the main power to the front seats has to be connected to different terminals in the Rear SAM so that power is cut after a period of time after switch off, otherwise the seats cause a parasitic drain and it will kill your battery over a few days as they will always be live.

If you have patience than you can read the wiring diagrams for your model and work it out and it all becomes clear.

It took me a few months to complete my conversion / retrofit and most of that was reading forums, studying wiring diagrams and sourcing used parts to keep the cost down. Fitting it was actually the easy bit once I knew what to do.

I do now find it incredibly satisfying to be in the cabin surrounded by my hard work and I get to play with the fruits of that labour.

Good luck!

 

[KevinH2000]

Thank you for your reply. Your summary of the process is consistent with the information I gathered. At this time I am attempting to find out how to establish communication between the seat control module and the control in the door. I may have questions for you after I have spent some time exploring the existing wiring in my car.

 

[KevinH2000]

The CAN BUS is basically a network that runs throughout the car and is connected to various modules and ECUs. It carries signals that enable activation of various services and / or modules within the car. The memory function for the seat is made possible by the Seat Control Module underneath the seat and it is THIS that needs to be connected to the CAN BUS.

If you already have the seat movement functions on the door panel then your seat is indeed connected to the CAN BUS (or the functions wouldn't work).

This is a stab in the dark without actually seeing the seat but I would guess that you need the new seats with Seat Control Modules underneath that have the memory ability. Door card seat controls that have the memory facility and some coding to enable the car to see the new feature.

Do also be aware that on the S212 (I did the full memory conversion including steering column and mirrors etc on mine) that the main power to the front seats has to be connected to different terminals in the Rear SAM so that power is cut after a period of time after switch off, otherwise the seats cause a parasitic drain and it will kill your battery over a few days as they will always be live.

If you have patience than you can read the wiring diagrams for your model and work it out and it all becomes clear.

It took me a few months to complete my conversion / retrofit and most of that was reading forums, studying wiring diagrams and sourcing used parts to keep the cost down. Fitting it was actually the easy bit once I knew what to do.

I do now find it incredibly satisfying to be in the cabin surrounded by my hard work and I get to play with the fruits of that labour.

Good luck!