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I had one remaining issue and it was important that I address it properly. After I installed the passenger seat, the SRS light illuminated on the dashboard and the center display showed an air bag message instructing me to take the car to the work shop. I was able to resolve the issue by installing an occupant classification module from a W203. I found it on an auction site for $40. The sensor was from a 2006 model, but I think the 2005-2007 models use the same sensor. I didn’t “cannibalize” parts from my C230 seats because I may sell them and I wanted to leave them intact. Occupant sensor control module and wiring from a 2006 C230
Unfortunately, the module wasn't "plug and play." Mercedes changed the connector that attached the control module to the seat occupancy pad.
W204 Connector - Left W203 Connector - Right
Fortunately, I had a W204 Connector left over from the wiring harnesses I modified to power and control the seat motors. I soldered the W204 connector to the W203 seat occupancy classification module. I had to guess which wires to connect.
W204 Connector soldered to W203 Seat Occupancy Control Module
Fortunately, my first guess turned out to be correct. I simply oriented the plugs the same way and attached the wires in the same order. The wire color scheme is:
W203------------------ W204
Red/Yellow----------- Pink/Black
Blue/Yellow----------- Solid Blue
Blue --------------------Brown/Blue
The W204 module was riveted to the seat frame. I drilled out the rivets, removed the W204 module and attached the W203 module using wire ties. W203 Module installed in seat bottom
I then ran the seat belt wire to the location on the outside part of the seat, cleaned up the wiring and installed the seat.
When I turned the car on, the SRS light went off after a few seconds and there was no error message on the display. When my wife sat on the seat, the "Air Bag Off" light went out.
Everything seems to be working correctly and safely.
Last edited by KevinH2000; 04-26-2019 at 10:41 PM.
Good for you! That’s GREAT!
Love posts like this of people modding and keeping their w203s new, fresh and as amazing (if not MORE THAN) new! Love it!
Thanks - I agree wholeheartedly. An occasional upgrade keeps the car from becoming stale. The stock C230 seats are better than the seats you find in most sports sedans, but the the fully adjustable (and full leather) C63 seats are a significant upgrade.
Two month update and repaired the tear in the passenger seat
The repairs to the bolsters appear to be holding up well after two months. I will post another update in two or three months to see if the heat of the summer has had any detrimental effects.
I had a small tear in the seat bottom of the passenger seat. Although dying the seat disguised it, it was still fairly visible:
I used a product recommended by the company that sold me the dye to fill the crack. It was a little pricey, but I will be using the leftover filler to repair a steering wheel so the cost will be spread over two projects.
The tear is less prominent after using the filler, but I can still tell it is there. The flash makes it more visible than it does under normal lighting conditions.
Although the repair isn't perfect, I think filling the tear will prevent something from catching the edge of the damaged area and making it worse.
So this was only possible because you found a connector in the seats for the non-canbus door switch. Did you completely bypass the computer then?
Yes-I decided that I would focus on making the seats work and fixing the cosmetic issues.
If I ever have some time, I may track down a set of interior door panels with the memory switches and see whether I can make them work in my car. Although I'm sure anything is possible if I am willing to put the time and money into it, the technology changes between the W203 and the W204 make it unlikely that the set up will be "plug and play."
KevinH2000, thanks for much for posting this detailed thread. With the pin assignments, this morning I was able to remove a pair of C63 seats from a local yard for the princely sum of C$80 total! I have saved the thread to PDF and will look to install the seats into my C55 AMG at some point in the future!
I am glad the thread is useful. In retrospect I enjoyed this project, but there was a time before I sorted out the wiring that I thought I had two large paper weights. $80 Canadian is a great deal. I paid $300 U.S. for mine and I thought I did well.
My wife’s cousin has a C55. The interior is a step up from that of the C230. I am interested in your opinion about the merits of the C63 seats versus the C55 seats because my original plan was to swap is C55 interior into my car. I would also like to know whether you are able to use the door switches and memory function in your C55 to control the C63 seats. If you can, I may see whether I can source some door cards with switches and add memory to my seats.
By the way, one of the previous owners installed a set of CLK wheels on my car which appear identical to those you use for your winter tires.
I've driven a C63, but quite some time ago. A friend who has more seat time in them (though not owning one), said he liked the C55 seats more than the C63. He felt the C63 seats were too bolstered. I do like the C55 seats very much - they give quite good support without being too 'much', but I prefer more bolstering than not, so I think I will enjoy the C63 seats.
I suppose I will plug and play and see if the memory function works. That would be great, though your process would certainly be fine by me. If for whatever reason I don't like the C63 seats in the car, I will make some real furniture out of them.
You mentioned you have a Boxster - I'm on Rennlist with the same username. My 997 came with regular (but powered) seats. I bought a set of Porsche Adjustable Sport Seats from a fellow that came out of a 997 GT2. They bolted in and were plug and play - but I stayed within the generation - both my car and the donor car are 997.1s. That was easy, but I really enjoy the sports seats in the 997 much more than the original seats.
I haven't posted up much on MBWorld for quite a while, but I sold those 17" CLK wheels this past spring. I've now gone back to the factory C55 wheel and just mounted winter tires. I added a 6/4 piston big brake kit from an early CLK55/SLK55 and those calipers wouldn't clear the 17s, so I got rid of them - ironically to a 204 C63 owner who just wanted a pair to mount drag tires for the rear for days at the strip. Those CLK wheels definitely have much less offset than even the factory C55 wheel.
Might be a few months before I attempt the seat swap; but I may compare the plugs and such sooner - I'll post up my findings.
Well, last night I put in the driver's seat, and it went really smoothly!! As expected, the seats bolted right in. However, I had to swap the memory modules over. Although externally they are visually identical, they have different part numbers. Initially I tried just plugging in the C55 chassis harness into the C63 memory module, but no dice. Swapping the memory module immediately cured that.
However, that left the airbag/seat buckle sensor - I was getting an error because I did not plug that in. The C63 has a large yellow connector with three plugs inside it; the C55 just has one small two pin connector. Swapping over the C55 buckle and harness to the C63 seat cured that.
The seats move in all directions per the C55, with the exception of the powered headrest as the C63 seats have fixed headrests of course. The memory and convenience entry functions also work. Seat heaters work, which is a bonus because since I've had my C55 since 2011, the heaters haven't worked! I actually have some aftermarket heating pads that I was going to install on the C55 seats but won't need to do that now. The lumbar adjustment does not work though, not sure if that would just need power or if it's involved with the memory module - I'm pessimistic and think it would need to go through the memory module. I have two extra plugs hanging off the C63 seats one, one smaller two prong, white plug, and the remainder of the airbag connector. Perhaps the white plug has to do with the lumbar, so I need to investigate some more.
Everything bolted in nicely, including both the male and female seat belt buckles. Even the plastic covers on each corner at the end of the rails fit from the C55 (the ones on the C63 broke when I was removing them from the wrecked car, so I thought I would have to buy new ones) Very impressed, everything is 100% reversible, and very happy with heated seats as I am winter driving my car again.
As noted previously, the plastic panels on the outer edge of the seat is very close to the b-pillar trim, and contacts it gently but I can live with that.
I will post some pictures once I figure out the images on my phone.
Here are photos of the memory modules - as stated, they look externally similar, and even the markings on the pin assignments (on the outer edges of the part number labels) are the same, but nothing happened when I plugged into the C63 module. Notably, the C55 module has a 211 part number. The memory modules are held in with plastic clips that need to be disengaged, two at the rear, two at the front.
The two extra plugs are shown. On the yellow plug, there are actually three plugs inside with male pins. As I didn't want to cut anything, I managed to remove the smallest, two pin plug, then left the whole connector with the two other plugs inside it hanging under the seat. I'm not sure what the white plug is about, so I will review the thread and also the WIS for more details later.
This is a photo of the female buckle, Now I can't remember if this was the C55 buckle or the C63 buckle, but they also look similar. I know that the car I took the seats out of was in a front end accident (passenger strut tower pushed nearly to the firewall, and airbags deployed) so good idea to swap in my known quality C55 buckle. Whilst the C63 buckle did fit the C55 male buckle, its action wasn't smooth, so better to replace anyway. The wire to the air bag sensor just runs along the side of the seat, and is held in with the metal clips (one only seen in the photo). The other two lines are for the side airbags; on the C55 there is just the one wire, on the C63, there are a total of three.
I swapped this little bracket over because the one in the C63 was busted. In retrospect, I could have just unclipped the C55's two pin yellow airbag connector, removed the larger C63 airbag connector, and slipped the C55 airbag connector into the C63 bracket. Note on removing this bracket - the plastic 'bridge' in the centre has a little bump in it, pry down on the bridge, then the whole bracket moves to the side and releases.
Finally, two photos showing the clearance on the inside and outside edges of the seats. Inside much better than outside, but outside is tolerable. I do need to buy another seat belt buckle cover for the C63 seats, mine was missing one when I removed it from the car. Fortunately, I have the cover for the passenger side.
Those seats appear to be in better shape than mine and you paid less than a third of the price I paid. I agree that they are a tight fit. (When I installed mine, I had a period of about 5 minutes during which I was not sure they were going to fit. I remember breathing a sigh of relief when I finally jockeyed them in place.) They also seem to take up more of the rear passenger leg room than the stock C230 seats. The C55 seats may be larger than the C230 seats and there may not be a noticeable difference in your car.
I need to take a closer look at your post, but for now I have a couple of suggestions:
1. Regarding the bolsters and lumbar supports - Look at post #20 and see how I applied power and ground to the smaller black connector. You will have to do this differently than I did because you are using the original seat wiring harness. Maybe you could just tap into an unused slot in the fuse block to the left of the steering wheel.
2. Seat belt warning light - Look at post #26. You may be able to swap the seat occupancy sensor in the passenger seat for one from a post-facelift W203. That's what I did and the warning light went away. The SRS system may be looking for a specific signal from the occupancy sensor and if it doesn't receive it, the system triggers the light.
Thanks for the information on the seat memory modules. If I can obtain some W203 door cards with the switches and the seat modules from a compatible car. I may be able to add some functionality to my car.
Also take a look at post #18. This provides more information on the bolster and lumbar controls. If you can find a way to supply +12 volts to the white wire on pin #2 of the 6-pin black connector and ground the brown wire on pin #4 I expect your bolster and lumbar controls will work.
.
When I work on projects that require 12 volt direct current I use a power supply scavenged from a discarded personal computer. (There are several videos on YouTube that show how to do this.). This helps to test various wiring combinations with the components out of the car.
Jake - I cannot think of anyone who needs (and deserves) a pair of C63 seats more than you do. I hope you find a deal like Saabotour’s. By the way, I drove about 300 miles today. I kept thinking that Distronic would be nice on long drives.
Kevin, thanks again for the insight. I think I have the lumbar controls sorted out.
The white plug present on the C63 chassis harness is not present on the C55 chassis harness, but on the seats, these run power and ground to the lumbar controls. Yesterday, I actually also took delivery of a Star/Xentry clone system, and the laptop included WIS, so today I surfed around there a bit. The WIS documents confirm that the pneumatic pumps are integrated into the seats themselves, as your previous experiments found. Anyway, I stopped looking when I found the wiring diagram and figured I should get back to doing some 'real' work.
But this evening I ran power and ground to the white plug (only two prongs) and the lumbar switches. This was on the passenger seat in my garage, as it's not yet installed. The switches seemed to work immediately.
My testing gear is pretty rudimentary - I have a Noco jump start battery, and I ran some testing leads off that, then connected them to the prongs. I used this same process to jump the pins when the seats were still in the car in the yard, except I also used some small screwdrivers and picks to trigger the pins.
The larger white connector and I think the smaller black connector you are talking about in your posts are already plugged into my C55 (but with 211 part number) memory modules. As long as we're talking about the same ones anyway. So I'm not sure I will tap into those, as everything seems to be functioning correctly as the seat 'thinks' it's a C55 seat still. There are no lumbar controls on the C55 seat, so I think I want to keep it that way without mucking around. But it seems that the small two prong white connector is independent and as long as power and ground is supplied, they'll operate the lumbar controls.
Then two other questions arise - whether the C63 lumbar controls are part of the system memory; and how large of a fuse should I run to power to them? I will surf around to see if I can find a C63 fuse diagram to deal with the latter. I did find a 2010 C-Class owners manual online and it said that every once in a while you would need to readjust the lumbar, so I expect there is a bit of air bleeding out. I hope the systems are more reliable than my old C43 seats - they had pneumatic bladders too, but mine never seemed to hold air for more than 20 minutes or so. As for lumbar memory settings - I suppose I can unravel the rest of the cut-off chassis harness to trace the wires off that two prong white connector and see if they head into the memory module. I suspect they do to preserve the C63 settings, but again I'm not sure I can actually make that work on my C55 given that the memory module wouldn't know what to do with the lumbar. Does that logic make sense?
This is the shot of the connectors on the passenger seat, essentially the same as the driver's seat. The two prong white connector is on the right, just on top of the yellow airbag connector. At the bottom of the photo is the remains of the harness on the driver's side I cut off the junkyard C63.
Close up of the white connector. Using typical German car wire colour logic, I figured that brown was ground, and therefore the other must be power, and tested accordingly.
Here's a close up of the buckle on the passenger seat, and the wiring that leads to the white and yellow connectors. The white marking leads to the white connector so must be for the lumbar controls; and the yellow marking leads to the yellow airbag connector. On the driver's side, when I removed the whole buckle the wiring came with it. I intend to do the same on the passenger side with the buckle I take off the passenger side. I suspect that is when I will be taking out the occupancy sensor from the passenger seat too, but I haven't gotten that far yet. Note the 211 part number on the buckle.
Nearly there - passenger seat is in, and everything wired up except for the lumbar buttons.
As with the driver's seat, I swapped over the memory module and the female seat belt buckle. The buckle included the seat belt sensor. Once again, the C63 passenger seat has a large yellow airbag connector, and within it are three connectors inside. One is the seat belt sensor (like on the driver's side), the other is the occupancy sensor (which leads to under the seat leather), and then the other one, which must be for the side airbag.
On the C55, there are only two airbag sensors, one that is on the seat belt buckle, and the other is for the occupancy sensor, which also leads to under the seat leather. But instead of swapping the sensors over, I swapped the connectors. That is because on close examination, the connectors are different, but both only have three wires. However, the connectors are a different shape, and the C63 connector would not mate up to the C55 connector. But the wire colours are the same, though arranged in different pin assignments.
C55:
1 - brown
2 - red
3 - white
C63
1 - brown
2 - white
3 - red
Other than that, it was pretty straightforward, everything bolted or connected up, as expected.
C55 occupancy sensor connector, note the horizontal arrangement of the pins.
Unpinning the C55 connector - pry up the flap with a small screwdriver, then depress the pin retaining tab with a small pick.
C63 occupancy sensor connector - note the different pin layout.
Unpinning the C63 connector, same idea as the C55 connector, but there are two flaps instead of just one.
Reassembled wiring underneath the passenger seat, yellow connector on the left is from the seat belt buckle; the other is the re-pinned C55 connector on the C63 occupancy sensor, still in place under the seat leather. I taped up the large connector and it's just hanging out of the way under the seat.
This is a close up of the C63 chassis wiring harness where I cut it off from the car. The brown wire and the red with white stripe wire lead to the white connector, which supplies power and ground to the lumbar buttons. These arrangements should be the same on the driver's side. It appears that the white lumbar connector wires do not lead to the memory module, so that is encouraging, as it would be 'stand alone' from the memory module, and I'm speculating as simply power and ground and then it should be all fine. So I'm hoping that the final steps will be to cut off the white connectors from the C63 chassis harnesses, then run power and ground to them, and then that should complete the install!! That should be relatively easy, for now I'm going to enjoy the seats, especially in the corners, and especially with heat now it's getting cold (ironically it's going to be 15*C this coming week so I'll be driving my other car for a few more days!).
As before, the plastic covers on each corner of the seat rails from the C55 slipped right onto the C63 seat rails. I have also ordered a new plastic seat belt cover, surprisingly only C$14 from my independent Benz mechanic (who order it from the dealer). Does have to come from Germany though. But that's cheaper than the used ones on eBay!
Great job. I think you are on the right track with the wiring for the lumbar and bolster controls. Regarding whether the lumbar and bolster settings are stored in memory - I suggest that you post a question on the C63 forum. The members on that forum should be able to tell you whether their cars retain those settings. My guess is that they don't. Even if they do, you probably won't be able to replicate it because you are using the C55 seat control modules.
Picture #8 in post #38 has a side-by-side photo of the C63 driver's seat and the C55 passenger seat. The contrast in the amount of side bolster support is striking. The C63 seats are significantly better. In an earlier post you mentioned that you installed sports seats in your 997. I've made some upgrades to the seats in my 986, but I am not satisfied with their lateral support. When participating in a driver's education event at Virginia International Raceway, I was sliding all over the seat. The C63 seats would be great for DE, but I doubt they will fit.
I'm envious of your ability to use the memory function. In order to avoid wear on the bolsters, I move the seat back before exiting the car so that I don't have to drag my butt across the bolster. Having the seat take care of this automatically will be a convenience. If I ever see someone parting out a C55 locally, I will be looking for the parts needed to upgrade to your level of function. For now, I am acknowledging that you have superseded me as the C63 seat swap guru.
Kevin, you are far too kind in your praise. To quote Sir Isaac Newton - "If I have seen further it is by standing on the shoulders of Giants." I would have never gotten this far without your post of the pin assignments, and I think you did far more work to make the seats work in your car. All I did was some Lego-like plug and play work. If you insist on passing on the seat swap guru moniker to me, then I think you should be deemed 'C63 seat swap Meister'!
My 997 originally came with the normal seats as well, which I found a bit odd because it was pretty highly spec'd with the very expensive X51 Carrera Powerkit option, plus Sport Chrono and factory short shifter. Maybe the guy ran out of money after checking all those boxes? In any event, a few winters back I found an ad for a set of sport seats that actually came out of a 997.1 GT2, with alcantara centres. I actually preferred standard leather over the alcantara, but the price was very good and not having to ship (I drove 3 hours each way to get them) was a plus. On a recent Porsche club autocross, I found the lateral supports sufficient, and they are 'streetable' enough on the seat. I once had a ride in a 997.2 GT3RS with the carbon buckets and those were more of a chore to get in and out of, but the sport seats are just fine I think. In any event, my sport seats were plug and play as well, as my standard seats were powered, so it was an easy swap.
By comparison, the C63 side bolsters are probably even bigger than the 997 sport seats. I'm now very happy with my auto seats. Next will turn to some other 203 mods to keep me occupied and out of trouble.
Those 997 seats look like they would do a better job of holding me in place than my seats. It looks like the middle of the seat is Alcantara which must be significantly grippier than smooth leather.
The seats currently in my car are from a 996 Turbo that the owner had converted into a track car. Like your 997, it does seem odd that a high-performance version of a vehicle would be equipped with comfort seats.
Returning to the subject of C63 seats - I think it is great that the next person who decides to pursue this modification will have his or her choice of two viable options. You've also given me a clear path to upgrading to memory seats if I choose to proceed with an enhancement. I've been scavenging parts from a C230 with a broken timing chain. It did not have memory seats, but if I ever see someone parting out a compatible vehicle with memory seats, I'll know what parts to grab. I will need to puzzle out the wiring between the door controls and the seats, but if I have access to the donor car a little exploration should yield the information I need.
If my donor door has a module - I’ll send it all.
(Need to swap out my passenger front due to rust...)
Thanks Jake. I have compared the door panels with the seat memory control to those without the control. It doesn’t look like there will be a cosmetically acceptable way to add the control to the door panels in my car . I probably need to obtain the entire door panel. I may start watching the local pick and pulls to see whether I can find a deal. One other concern is that I have seen some threads which indicate the W203 memory modules can fail and cause the battery to discharge.
Right now I may be a little weary of working on the car after my self-inflicted electrical system woes. (Which were made worse by my foolish mistake of seeking help from the dealer.) But, I have a feeling that I will recover at some point during the winter and start thinking seriously about this.
I think the seat memory module battery drain issues were on the pre-facelift 203s. Even if they do fail that way and drain the battery, there are known fixes out there to convert the 12v constant to 12v switched and issue resolved - but then no convenience entry. But I think those battery drain issues were resolved with the facelift. I posted earlier that the memory modules had 211 part numbers, so today I went to the yard to look for spare modules out of a 211 there. However, it seemed that particular junkyard car had different modules, so I left them.
I found a pretty well spec'd pre-facelift C320 and grabbed the door switches as I am planning to build a base for my C55 front seats and put them in the office here. But I've also been talking about converting one of my 997 seats into an office chair for over a year too, so both projects may take some time.
04-23-2019, 10:58 PM
