This is a project i just did in the weekend, and because there was almost none information on this online, i thought it would be a good idea to share the details on this retrofit with you. But first, little backstory.

I own a C200 2008 W204, which is a really nice car, but unfortunately it doesen't have Memory Seats, only semi-automatic seats, and this is of course a good reason to do a nice retrofit!

So, many thanks to @KevinH2000 for his answers to my questions in here, because of his experience in retrofitting seats from C63 in a W203.

Big thanks to my friends who helped me make this possible. My good friend the CAN Nerd Marc helped me do the wiring.

Parts List - What do you need? - I will write the part numbers i have here:


Parts List

2x Fully automatic seats

2x Door panels with Memory - OR INSTEAD 2x Memory Module, 2x Door Harness from a car with memory. The standard harnes does not, i repeat does NOT have the connector for the memory module.

Front Passenger Side (Right Side DK) Door Module capable of memory
A 204 870 22 26

Front Drivers Side Door Module
(Sorry, forgot to take picture of part no.)

2x 14-Pin Connectors to seat controller
A 220 545 37 28

4x Pins / Pin contacts for 14-pin connector
A 013 545 15 26

2x 2 Pin Can Connector (THIS PART WAS NOT THE 100% FIT, BUT WE USED A KNIFE TO CUT THEM TO FIT, DEALER COULDN’T FIND THE RIGHT PART FOR ME, BUT THIS CAN WORK IF YOU CUT IT)
A 025 545 04 26

4x Pins / Pin contacts for CAN 2-Pin Connector
A 013 545 46 26

Wire for CAN connection. I bought 10 meters of yellow and 10 meters of black 0.75mm wire. Preferebly you should use brown and brown/red wire, but they didn’t have it in the store when I bought.

BEFORE YOU START, DISCONNECT POWER TO THE BATTERY TO AVOID SRS ERRORS AS THEY WILL NOT AUTOMATICALLY RESET, WHICH MEANS THAT IF YOU DO NOT REMOVE POWER AND REMOVES THE SEAT YOU WILL GET AN AIRBAG ERROR

1. Remove the seat
2. Take the 2 pins out of the existing connector to the seat controller
3. Take your wire and make use of 2 pins and 1 CAN connector and put it together.
4. Cut the connector with a knife so it fits the CAN B Hub (Skip this step if your dealer could find the right connector instead of ordering the one I have described in the parts list.)
5. Remove the carpet and find the CAN B Hub and click in the newly created connector. Picture one is zoomed out, picture two is zoomed in. The Yellow and Black wires are the ones I have used
   
   Drivers side (LEFT) CAN B Hub W204 Location
   
   
   Passengers side (RIGHT) CAN B Hub W204 Location
   
   
6. Assemble the 14-Pin Connector as follows on the picture
   
   a. Brown = Ground
   
   b. YellowBlack = Constant Power
   
   c. Yellow = CAN HIGH
   
   d. Black = CAN LOW
   
   
   14 Pin Connector with new wiring, Of course the CAN B High and CAN B Low colors depend on which wire color you use. Original CAN B colors are BrownRed for CAN H, and Brown for CAN L
   
   
   
7. Assemble seat again in car with the connectors plugged in
8. Remove the door panel
9. IF YOU REPLACE THE WHOLE PANEL WITH A NEW ONE ALREADY CONTAINING A SEAT CONTROL PANEL SKIP TO STEP 12
10. Remove the wood trim and insert the seat control panel
11. Replace the wiring harness with the new one, and connect the connector to the seat control module afterwards.
12. Replace the door module with the new
13. Mount the door panel
14. Mount the seat
15. Connect to the car with vediamo to CGW 204 and set variant codes 241/242 and 275.
16. Connect power to battery

 

Congratulations on your successful project. Don't be surprised if someone contacts you in 5 or 6 years with questions.

It is interesting to see the subtle changes from the W203 to W204. The seat memory system seems to have the same basic architecture, but the part numbers and locations of the CAN blocks have changed.

Your work illustrates the value of the forum. I started with a basic seat swap. Another forum member added information about seat memory in the W203. Now, you have built on the previous work and added additional information to complete a W204 project.

Have you been able to add the "easy entry" feature. In the W203 activating the memory seat function adds a selection on the center screen menu that allows you to activate easy entry. See post 38 of this thread for details.

One other note - In September, I had a mishap in a parking garage which damaged my exterior passenger-side mirror. I replaced it with a used mirror that came from a car with the memory package. My previous activation of the memory function for the seats also enabled the memory mirror. If you can find an inexpensive memory mirror at a "pick and pull" it will be a nice addition to the car especially if more than one person regularly drives the car.

 

@KevinH2000 Unfortunately i cannot make easy entry / exit work. I would very much like the feature, but i'm not sure it is possible in the W204 Pre-Facelift, as no menu item is visible. Otherwise it should be another variant coding that i don't know.

 

This video shows how activating the easy entry feature should proceed in a W204:



If I understand correctly, the option for activating the easy entry feature is not available in your convenience menu. If that is correct, you may need to have someone with a Mercedes Star Diagnostic system code it for you. I am not familiar with the Vendiamo system you used to code your memory seats. It may not have all the capabilities of the Star system.

I understand that you are in Denmark and auto repair shops may operate differently in Denmark than in the U.S. In the U.S., I would recommend that you contact an independent Mercedes repair shop and ask whether they had the Star system. If they did, I would ask whether they were able to code the memory seat function for you. In the U.S., the shop would charge for an hour of labor to do this.

In the U.S., some shops are more helpful than others regarding customers who perform repairs and upgrades on their vehicles. If you can find a helpful mechanic, you can share this thread, and the mechanic should be able to help you.

Good luck.

 

To clarify, the required parts for the door panel are: the control buttons, door module and the wiring harness from a car with memory seats?

As in:
Front Passenger Side (Right Side DK) Door Module capable of memory
A 204 870 22 26

Front Drivers Side Door Module
(Sorry, forgot to take picture of part no.)

are equal to 2x Memory Module

 

You need:
Wiring Harness for inside door with memory.
Memory buttons
door module.
I have the part no. for LEFT FRONT (Drivers Side Europe) which is A 204 870 22 26 as written in the tutorial.

Hope it helps!