In the MB WIS system (werkstattinformationssystem) there is under group 91.30 a document labeled 91.09 "Installation Instructions for Special Equipment - Seat Heater for Front Seats" which is illustrated and very comprehensive.

It lists SA 56154 which is the controlling document for this system and the number used to look up parts for this retrofit.

Using these numbers, perhaps your dealer or independent can check parts availability

 

In the MB WIS system (werkstattinformationssystem) there is under group 91.30 a document labeled 91.09 "Installation Instructions for Special Equipment - Seat Heater for Front Seats" which is illustrated and very comprehensive.

It lists SA 56154 which is the controlling document for this system and the number used to look up parts for this retrofit.

Does anyone have access to this document or post it...I would like to perform this upgrade

 

Thank you! I'll pull up the doc and get started. It's a few months from getting very cold here, even then it's not super cold but it's sure nice to have heated seats.

I'll post a follow-up once I've gotten everything done.

Regards,
Walter

 

My 88 wagon has the heated seats. Oddly, the only other 124 I've seen with them was another 88 wagon that I passed on.
Installing the heated seats would be a nasty job. There are heating grids installed in both the backrest and cushion parts of the front seats. You'd have to disassemble the seats to install these parts. Of course you could use heated seats from a donor car if you could find an interior match.
Then there's the wiring. IIRC there's a relay or controller under the carpeting in front of each seat. The wiring looks pretty beefy.
Beyond that you'd be installing wiring for the switches inthe console and up under the dash into the underhood fuse box.
And you're uncomfortable in Dallas? LOL It's about 25F here in SE PA right now.

 

The heating elements are stitched into the padding of the seats so any shifting of the pads is minimized in the stock seats. You would really need to patch into the harness a couple of places to make this happen.

An inexpensive, and VERY viable alternative is to buy aftermarket seat heating pads. They only require a 12v power source and you to take the seat covers off and affix the pads. I would strongly suggest paying the extra bucks to have an auto upholstery shop do the fitment as they have the correct tools to stretch the leather over the bolsters and put everything together correctly. That way you don't have wrinkles in the leather, it is as tight as it was prior to the removal and you don't lose skin trying to form leather over the padding and frame [experience says that without the right upholstery tools, you WILL bleed].

You end up with a very small button that pops up between the seat and console which turns the seat heaters on and off. A much more simple solution in my opinion than trying to retrofit and splice into the wiring, get a new console wood piece, new buttons, etc.

 

67 and u are cold ... we have 26 F here in Chicago...

 

I have the 95 e320 heated seats in the car now but want to make them operational. Just wanted to know if anyone had compiled a parts list needed to complete the project...( including MB part numbers)

Also wanted to know if anyone had access to the WIS program and pull up (group 91.30 a document labeled 91.09 "Installation Instructions for Special Equipment - Seat Heater for Front Seats")

Thanks for your time.

 

I added heated seats to my 1987 300D this summer. You don't need the WIS document, it's pretty straightforward. What you need is:

1) A pair of heated seats (used)
2) The main & secondary wire harnesses (new from dealer)
3) Relay (used)
4) Left & right console switches (new or used)
5) Console wood with extra holes (new or used)

Note that depending on year of your car, and the year of the donor seats, and if each has memory or not... you may need to swap bases (i.e., install the heated seat frames & cushions on your existing base/motor assembly.) I had to do this on my car. The 86-90 motor controllers are different than 91-95, ditto for with & without memory.

Then, you need to remove all the seats from the car, remove the main floor carpet, loosen the center console, and wire it all up. I live in an area with cold winters and the upgrade was worth it. My other two 124's came with heated seats from the factory. BTW, the parts I mentioned to buy used are the ones which are too expensive new. The ones marked "new" are not worth trying to source used, unless you can access a Pick-n-Pull car to get them from. It's too much work to remove the wire harness from a used car, most salvage yards will want too much $$ due to the labor. Photos of the whole project are at this link:

Index of /images/W124_seats

Here's some of the important ones:

 

Perfect! thats the info I was looking for.

Thanks!

 

This is an old and great thread any pictures on how it all goes in?

 

I have assembled my kit to undertake this project on my 88 300CE and as soon as the stitches in my hand come out I'm putting in the wiring. I took apart two and a half JY cars trying to get a main harness as those are now NLA. I ended up looking for a used one as the junkyard ones were horribly trashed and found you can buy one from Socal Mercedes Parts for a hundred bucks. The one I bought is in pretty good shape.

It's really conceptually easy. You take out the front seats, the driver's side back seat (or whole thing if not a coupe) the carpet on the entire driver's side, the console, and the kick panels under the steering wheel. There will be a set of plastic wireing panel containers along the driver's edge of the car. Open those and insert the main wiring harness. The end with the large plug (see dave's pics) goes through the hole in the sheet metal into the cavity under the back seat. The relay gets attached to the sheet metal back there and the large plug goes into the relay. At the front of the driver's seat base area, there is another plastic channel going toward the hump. All of the wiring save the driver's seat connection, the power connection, and the auxiliary plug go into the cross channel there. Under the console there is a post with several ground wires already attached under a nut. The brown wires on the harness get added to that post. The switches stay in that area as well. The passenger seat connection goes over the hump and joins the seat wiring connections on that side.

The power end of the harness stayes in the longitudinal channel to the front of the footwell. On the outside part of the well is the auxiliary plug terminal and that plug goes in there. The power plug goes through the firewall.

The power feed harness gets cinnected to the bottom of the fuse box, to the fusebox power feed under the relays. The connection is to the round connection. The pins go into the fuse box which you can mount anywhere on an accessible bolt, and the black plug then goes down along the firewall to meet the main harness plug and they connect.

I'm recovering my front seats with new leather at an upholstery shop and the shop will be insterting the "tines" of the heating pads into the pleats of the new covers as I did not find any suitable replacement seats with heat.

I do have to point out that this is going to be much harder than it sounds. Removing the carpet and the kick panels without a sawzall is a challenge, and the clips on the wiring channels look to be simultaneously impossible to open without force and easy to break. Getting the large plug for the relay through the sheet metal hole into the rear seat compartment looks pretty challenging, too. I'm a recovering lawyer, not a trimmer or a mechanic, so I expect my patience to be sorely tested.

When I do mine, I will take some pictures.

 

I wish I could find some decent seats for mine, I am sure the wiring would be easy from the stealership.

 

S124 relay location?

Do any of you wagon owners with factory heated seats, know where MB located the main heater relay (the big yellow one). On the sedans it's somewhere under the rear seat, so I assume the wagons are somewhat similar. I'd like to get started running the wiring under my carpet, but want to keep the relay in an accessible location for future service. Pics would be helpful if ya got em.

Thanks,
Casey

 

Both TEs i pulled heated seats from (90 and 92) had the relay mounted to the same bracket that holds the power window relay module and that thing is under the middle row seat cushion, drivers side. Bad pic but its the only one I have.

 

Thanks, that's very helpful!

 

I tried to pull the heating pads out of a deteriorated seat in the junk yard today. the way it is sewn in would have taken me an hour or more. I did manage to get the part numbers off the pads and have included a pic here.

I also pulled the yellow relay, the switches and the wiring stubs and connectors beneath the seats to build my own harness. I now realize that I did not get the small fuse box out of the engine compartment, maybe next week. These are out of a 91 300E.

Upper label on the left, lower on the right.

 

Hello everybody. This is already an old topic and so far it has been very useful to me. I fitted heated Sportline seats in my '90 260e Sportline since my old seat was worn. I bought all the parts which are shown on the pictures as seen in a previous post by gsxr.

Unfortunately I have a problem fitting the fuseholder: one part on the picture seem to be missing since the ''fuse holder socket'' cant be connected to the ''fuse holder bracket''. Hopefully somebody can let me know which part I still need to buy. Thank you in advance for your tips!

My Car :

 

The standard (non-Sport) seats have the heating elements sewn into the leather covers. You cannot replace the elements separately. The elements come with new leathers from Mercedes, which is pretty stupid, IMO (check the cost of new leathers and you'll see what I mean). That's why I said back in post #9 that if you want to add heaters, you need to obtain a set of heated seats to swap in.

Using generic heating pads, sorry, can't help there. No idea what the resistance or wattage is on the aftermarket stuff, how well it will transfer heat, if it will be even, etc. The factory setup heats up the side bolsters on both the bottom cushion and backrest. Not sure if you'd be able to get anything aftermarket to get that function.

:sawzall:

 

Thanks gsxr. I had seen (from your website? Or rybcc?) that they're stitched in. My old girl has mb text interior, so that's staying. The side bolsters would be nice, but I'll stick with just in the middle for bottom and back.

As to wattage; yep. Not sure.

There was a uk thread I think where someone had just installed the aftermarket ones and connected them to the factory connections, which would be a nice and reasonably easy thing to do (easy being relative in this whole process...)

 

found it; here's the link for the install of some waeco heater elements

Has anyone retrofitted heated seat pads to 124? - MBClub UK - Bringing together Mercedes Enthusiasts

cheers.

 

Don't know if anyone is monitoring this thread, but I was wondering a couple of things.

I wanted to use the existing wiring, but I don't have the heated seats, so

1) Has anyone tried aftermarket pads with the existing wiring? I don't know a lot about these types of things, but I gather that the pads are just big resistors, so I'm guessing that aftermarket with appropriate wattages should work. I admit that it's not clear to me how to get the hi/lo, my best guess is with different voltages. Does anyone know?

2) What's involved in putting the stock heating pads in a stock (non-heated, not sportline) seat? I gather (from this thread) that sewing is involved, but sewing doesn't scare me (ok, it scares me a little).

OK. Now I just sit back and wait for precisely the information I need to finish this project!

Thanks -- Greg

Oh, this is for the '94 E420 if that matters.

 

About to do exactly that ; factory loom and aftermarket pads. We don't have many cars here in NZ which came with heated seats, so having to make do. I'll post the results. I bought a set of Waeco pads to fit. Probably a month before it happens as the pads are coming from the UK.

It's been done before though in the UK. just do the old google thing

Cheers.

 

Greg, save yourself a lot of hassle, and just locate good used heated seats from a 1990-up W124. Then get the factory wiring harness from a donor car as well. Check with David Hendy, he's in the northeast and parts out a lot of 124's. He can probably supply you the wiring harness, relay, switches, etc and might even be able to get you the seats.

The heating elements are sewn into the leather. You can't buy the factory heating elements separately. You'd need to buy used heated seats anyway, remove the elements (if possible), and re-sew into different leathers. And this makes no sense at all.

Can't help with aftermarket options, sorry. I wouldn't bother with aftermarket as there are still plenty of heated seats out there available to swap in, at least in USA salvage yards. Get 'em while you can.

 

just bought a 94 w124 e320 coupe, need help!!

hello,

I just purchased a 94 e320 coupe with 123,000 miles and i noticed some quirks can anyone help me?

1) Car overheats when a/c is on
2) I have no interior lights on dash whatsoever, no guage cluster, radio or control lights
3) Car only starts in neutral

I only paid 1700 dollars for it so i expected to put some $ into it, but any help will be appreciated thanks.

 

hello,

I just purchased a 94 e320 coupe with 123,000 miles and i noticed some quirks can anyone help me?

1) Car overheats when a/c is on
2) I have no interior lights on dash whatsoever, no guage cluster, radio or control lights
3) Car only starts in neutral

1) Bad fan clutch, and/or radiator, and/or electric fans not running
2) Blown fuse
3) Bad or mis-adjusted starter lockout / neutral safety switch
4) Please post a new thread, nobody is going to see this post buried in a thread about heated seats.

Zeitgeist, can you move these 2 posts to a new thread?

 

Dave,

Thanks for the response. The pads are available (pn 124 820 27 98) for about $85 each. Of course, donor seats would certainly be easier, but I'm imagining that's an expensive option. Do you have David Hendy's contact info?

By the way, I note you have the '97 e420. How does that compare with the w124?

Thanks! -- Greg

 

By the way, I note you have the '97 e420. How does that compare with the w124?

The (early) W210 chassis is a very nice Toyota but a rather mediocre Mercedes, IMO. There are a lot of nice new features, but the build kwality is definitely a notch down.

The powertrain, however, is awesome. The late M119 is excellent and the 722.6 tranny is positively dreamy. The ultimate E-class would be a W124 with the late powertrain... shame the swap is borderline impossible (using factory electronics, anyway). Aftermarket ECU/TCU is an option but there are drawbacks, and it's not cheap, and it's not easy. Which is probably why I've seen almost zero of these swaps.

 

I'm not sure if it's a path you want to take, but Dorman (and others) make universal seat heater pads. I've never tried them, but it's not like it's a complex device...

http://www.amazon.com/Dorman-628-040-Universal-Seat-Heater/dp/B002U6IL9O

I'd imagine it's just a 12v supply, and there wouldn't be an issue using factory wiring to power the aftermarket grid. I don't know that for a fact, but again, it's not like it's a complex device.

 

Hmm. Now I'm curious. I looked at the schematic for the Dorman set up (I'll bet most of the afternarkets are the same) and essentially on High the pads are wired in parallel, whereas on Low they're in series, thereby doubling the resistance and halving the current, hence power, since the voltage (I imagine) will remain constant (I knew Ohms Law would come in handy one day). It's harder to see what goes on in the Mercedes circuit since the innards of the relay module are not described, but it is definitely not the same. It appears that the pads in the Mercedes are always in series, though there is a tap between the pads that is connected to the relay module. I suppose I could crack open the relay and try to figure out what's going on in there.

I'm going to try to wire everything up and see if I can't figure out a little more what's going on. Regardless, the pads themselves have no components, so they must be just resistors. Wonder what the resistance is? Anybody out there ever check the resistance of the Mercedes pads and/or the aftermarkets?

 

If you cannot obtain used factory heated seats where you live - like the fellow in New Zealand - then aftermarket heating makes sense, as it would cost a small fortune to ship seats overseas, and even shipping used leather covers alone wouldn't be cheap.

Greg, in Maryland, trust me... you're going to end up with a ton of work and a substandard result for little, if any, cost savings. Get good used seats from Pat Bartholow at Potomac German in MD, or David Hendy. If the leather isn't perfect, get the dye touched up at a local leather shop.