# E46 lumbar support retrofit DIY



## Terry Kennedy (Sep 21, 2002)

For some reason, my post over in the 3-series forum didn't seem to get a lot of attention, so I figured I'd post it here as well.

I have managed to retrofit the factory lumbar support option into my wagon. I wrote up a detailed DIY for it, which you can find here. Here are a few pictures taken during the install:


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## RChoudry (Jan 13, 2002)

this is really great, Terry.

If this was around with my last purchase, I would have skipped the premium package!


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## mquetel (Jan 30, 2003)

Wow, great job! That is an intimidating amount of work, but nice to know that it can be done. :thumbup: 

So... the important question: How does the lumbar support feel? Does it meet your expectations?


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## Terry Kennedy (Sep 21, 2002)

mquetel said:


> So... the important question: How does the lumbar support feel? Does it meet your expectations?


That's an interesting question. There is a lot of seat material between the pad and my back, so the changes with the pads inflated are pretty subtle. I have never used any sort of lower back support before, but as I take long trips (> 800 miles in 2 days) and was recently diagnosed with pinched nerves in my lower back, I figured it was worth it. I'll report back after I take one of those trips.


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## bmw325 (Dec 19, 2001)

Thanks Terry, for being the brave pioneer of the lumbar retrofit. I know its been kicked around for years, but you're the first person to jump in and do it.


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## Terry Kennedy (Sep 21, 2002)

robg said:


> I know its been kicked around for years, but you're the first person to jump in and do it.


Well, you know what they say about "fools rush in..."


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## Kaz (Dec 21, 2001)

Terry Kennedy said:


> Well, you know what they say about "fools rush in..."


As much as I appreciate the effort you've put into this, I don't think I've quite fallen in love with you just yet. :lmao:


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## Terry Kennedy (Sep 21, 2002)

Kaz said:


> As much as I appreciate the effort you've put into this, I don't think I've quite fallen in love with you just yet. :lmao:


This one, _not_ this one.


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## Kaz (Dec 21, 2001)

Terry Kennedy said:


> This one, _not_ this one.


 :rofl:

I wonder how different this is going to be for manual seats. There is no seat control module to plug the harness into, obviously. Unless there is another harness specific to manual seats, the power ones seem like they would work given you can get power and ground to the seat if the harness that's there doesn't already have that.


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## Terry Kennedy (Sep 21, 2002)

Kaz said:


> I wonder how different this is going to be for manual seats. There is no seat control module to plug the harness into, obviously. Unless there is another harness specific to manual seats, the power ones seem like they would work given you can get power and ground to the seat if the harness that's there doesn't already have that.


Well, the 401/402 harnesses are definitely the wrong ones for power seats with memory - I've never seen the connector they came with anywhere in my car:










So you might look to see if you have a matching connector in the seat area. I think I still have the connectors from when I cut them off the harnesses - if you want, I could send you one if it would help you locate its mate in the seat.

However, the pump shouldn't pull much current at all - the connector on the seat control module has pins that are just pushed onto the circuit board (not even soldered - friction fit) and the pump / valve system works fine. So anywhere you can tap 12V at a couple amps should work.


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## Kaz (Dec 21, 2001)

When I had the driver's seat out, there was only 1 multi-pin harness that ejects the same way all the big BMW harnesses (like the LCM or stereo amp) do, and I don't recall a 2nd one coming out of the floor. I'll have to check to see if the 4 or 5 wires down there all go to the pretensioner or not. If not, it should be fairly straightforward to steal power from under the console (maybe cellphone power when I switch to BT and take out the Mot kit) and route it to the seat harness.


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## Terry Kennedy (Sep 21, 2002)

Kaz said:


> When I had the driver's seat out, there was only 1 multi-pin harness that ejects the same way all the big BMW harnesses (like the LCM or stereo amp) do, and I don't recall a 2nd one coming out of the floor. I'll have to check to see if the 4 or 5 wires down there all go to the pretensioner or not. If not, it should be fairly straightforward to steal power from under the console (maybe cellphone power when I switch to BT and take out the Mot kit) and route it to the seat harness.


That's the harness that comes out of the floor by the vent and goes to the underside of the seat? Look for a heavy brown wire and a matching red wire with brown stripe - those are the power feeds, at least on cars with power seats.


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## Mr Paddle.Shift (Dec 19, 2001)

Terry, as always, your post is always a joy to read!  

Keep up the great job!


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## Terry Kennedy (Sep 21, 2002)

Mr Paddle.Shift said:


> Terry, as always, your post is always a joy to read!
> 
> Keep up the great job!


Thanks! What other options am I missing (besides a DIY Alpina conversion )?


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## Mr Paddle.Shift (Dec 19, 2001)

Active Ventilation Fans for the driver's seat. There is actually a retrofit kit for this. Includes 8 mini fans. 4 for the butt and 4 for the back. I told Kaz about this a while back. No coding required. Includes a side-mounted switch. These are pusher fans, not puller fans! The leather seat covers are perforated and will be VERY cooling for us So Cal folks in the summer. Alas...the price of the kit runs near a US$1000.00!! :eeps:



Terry Kennedy said:


> Thanks! What other options am I missing (besides a DIY Alpina conversion )?


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## JoeCinVa (Apr 26, 2002)

Mr Paddle.Shift said:


> Alas...the price of the kit runs near a US$1000.00!! :eeps:


And that doesn't even count the cost for the new perforated leather seat covers that are necessary. :yikes:


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## Mr Paddle.Shift (Dec 19, 2001)

Actually it does include the leather seat covers. The covers replaces the entire seat except the leather on the headrest.



JoeCinVa said:


> And that doesn't even count the cost for the new perforated leather seat covers that are necessary. :yikes:


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## bmw325 (Dec 19, 2001)

Mr Paddle.Shift said:


> Active Ventilation Fans for the driver's seat. There is actually a retrofit kit for this. Includes 8 mini fans. 4 for the butt and 4 for the back. I told Kaz about this a while back. No coding required. Includes a side-mounted switch. These are pusher fans, not puller fans! The leather seat covers are perforated and will be VERY cooling for us So Cal folks in the summer. Alas...the price of the kit runs near a US$1000.00!! :eeps:


Wow. very cool. Does BMW now offer this option on new 3 series in certain markets? Where? Or, is it only available as a retrofit kit? When did it become available? NOt that i'm willing to part w/ 1k to try it out-- but I'd never heard of this on an e46 before.


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## swchang (Oct 5, 2003)

Terry Kennedy said:


> Well, the 401/402 harnesses are definitely the wrong ones for power seats with memory - I've never seen the connector they came with anywhere in my car:
> 
> 
> 
> ...


Terry, I noticed your DIY now says that the 401/402 actually do fit. Have you found out if 403/404 is easier to work with, or would I be better off going with the 401/402 parts?


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## Terry Kennedy (Sep 21, 2002)

swchang said:


> Terry, I noticed your DIY now says that the 401/402 actually do fit. Have you found out if 403/404 is easier to work with, or would I be better off going with the 401/402 parts?


I don't know. I'm still running my modified cables. I think it was Kaz that tried the 401/402 w/ original connectors.


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## Kaz (Dec 21, 2001)

Terry Kennedy said:


> I don't know. I'm still running my modified cables. I think it was Kaz that tried the 401/402 w/ original connectors.


The connectors Terry shows are correct if you have manual seats. On power seats, this piece is already occupied by the main power/ground connection for the power function. On manual seats, the place that the pictured connector goes is empty, and this drops right in its place. You will need to buy the contacts that go in the car side of the harness to match.

http://www.bimmerfest.com/forums/showthread.php?t=68714


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## swchang (Oct 5, 2003)

Terry Kennedy said:


> I don't know. I'm still running my modified cables. I think it was Kaz that tried the 401/402 w/ original connectors.


Thanks. I sent you an email as well, BTW.


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## swchang (Oct 5, 2003)

Kaz said:


> The connectors Terry shows are correct if you have manual seats. On power seats, this piece is already occupied by the main power/ground connection for the power function. On manual seats, the place that the pictured connector goes is empty, and this drops right in its place. You will need to buy the contacts that go in the car side of the harness to match.
> 
> http://www.bimmerfest.com/forums/showthread.php?t=68714


Okay, so 401/402 for manual seats, 403/404 for power seats? So the ETK descriptions were incorrect?

BTW, anyone know why some of the older threads can't be replied to? :dunno:


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## Alex Baumann (Dec 19, 2001)

swchang said:


> BTW, anyone know why some of the older threads can't be replied to? :dunno:


http://www.bimmerfest.com/forums/showthread.php?t=101339


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## Terry Kennedy (Sep 21, 2002)

swchang said:


> Okay, so 401/402 for manual seats, 403/404 for power seats? So the ETK descriptions were incorrect?


I don't know, but I've ordered a full set (401-404) and I'll report back once I get them. I'm on the road now, so don't expect anything until after July 4th.


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## swchang (Oct 5, 2003)

403/404 appears to be the right wiring set. No soldering, heat tube shrinking, etc. needed.

I have my stuff hooked up but not completely installed yet. Just wanted to see if everything works. When I press the back button, should the pads deflate on their own? Or does it rely on pressure from the seat occupant to deflate?


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## swchang (Oct 5, 2003)

BTW, this is without the pad installed in the seatback. It's just sitting on the seat. Also, I did remove the black cap from the valve unit.


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## JoeCinVa (Apr 26, 2002)

swchang said:


> When I press the back button, should the pads deflate on their own? Or does it rely on pressure from the seat occupant to deflate?


It should deflate on its own.


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## swchang (Oct 5, 2003)

JoeCinVa said:


> It should deflate on its own.


Even when it's not mounted in the seatback?

Anyone have any advice on how to take the tubes off the valve unit? I've tried using a blowdryer, but it just makes the tube too hot to touch. Doesn't make it any easier to remove...


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## Terry Kennedy (Sep 21, 2002)

swchang said:


> I have my stuff hooked up but not completely installed yet. Just wanted to see if everything works. When I press the back button, should the pads deflate on their own? Or does it rely on pressure from the seat occupant to deflate?


Pushing the back button just opens the valve to let the pad vent out through the port on the valve that doesn't have a hose.

Removing the hoses is a bit of a pain - try to grab the end of the hose and peel it away from the valve port. Then wiggle and jiggle the hose, and repeat.

If all else fails, there should be enough slack in the hoses that you can use a razor blade to slit the end of the hose that is stuck to the valve port, remove it, and cut off the slit portion.


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## swchang (Oct 5, 2003)

Terry Kennedy said:


> Pushing the back button just opens the valve to let the pad vent out through the port on the valve that doesn't have a hose.
> 
> Removing the hoses is a bit of a pain - try to grab the end of the hose and peel it away from the valve port. Then wiggle and jiggle the hose, and repeat.
> 
> If all else fails, there should be enough slack in the hoses that you can use a razor blade to slit the end of the hose that is stuck to the valve port, remove it, and cut off the slit portion.


The one without the hose? You mean the one that the black cap was on? The three ports that were covered by the three-prong white cap should be connected to the red and blue tubes and the one pump tube, right?

I think there's plenty of slack in the red and blue tubes. I'm worried about the pump tube, though. It's already pretty short... Think it'll make it?


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## Terry Kennedy (Sep 21, 2002)

swchang said:


> The one without the hose? You mean the one that the black cap was on? The three ports that were covered by the three-prong white cap should be connected to the red and blue tubes and the one pump tube, right?


Yup.


> I think there's plenty of slack in the red and blue tubes. I'm worried about the pump tube, though. It's already pretty short... Think it'll make it?


 :dunno:


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## swchang (Oct 5, 2003)

Terry Kennedy said:


> Yup.
> :dunno:


Sorry, I meant do you think it'll still reach? Anyway, I ended up getting them off with the help of a friend. Pulled, used screwdriver, twisted, and kinked the tubes to cut off the vacuum. Hope the tubes aren't damaged now...


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## swchang (Oct 5, 2003)

Bought the rest of the parts. Very frustrated. Here's what's going on.

My pads inflate, slowly, but they inflate. I think this is the proper design. They don't deflate unless pressure is put on them. They do, however, deflate if pressure is exerted even while they're inflating! Thus, when they're mounted in the seat back under the wires, they deflate while they're inflating, and so they don't inflate AT ALL. I noticed that if you plug the exhaust port back with the little flimsy black rubber thing Terry's DIY says to remove, the pads can then deflate when the back arrow is pressed, and don't deflate as much when the forward, up, or down arrow to inflate is pressed. I suspect they wouldn't deflate at all if I had the black rubber thing seated fully, but I couldn't reinsert it properly after having removed it. Any idea what's going on? Did I remove the right black cap?

Also, just to make sure I have it right, the pump hose goes to the middle prong, while the blue one goes to the top (labeled B) and the red one goes to the bottom one, labeled R, which is also slightly out of line with the blue prong?

BTW, the 572 valve unit is the same as the 694 one except that the exhaust port is on the other side. Identical otherwise. 403/404 is definitely the right wiring set for power seats. I have memory seats, so dunno if that's required for a good fitting, but anyway... (Do lumbar settings get saved with seat memory? I don't think they do.)


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## JoeCinVa (Apr 26, 2002)

swchang said:


> Did I remove the right black cap?


I don't think there is any other black cap. Is there?



swchang said:


> Also, just to make sure I have it right, the pump hose goes to the middle prong, while the blue one goes to the top (labeled B) and the red one goes to the bottom one, labeled R, which is also slightly out of line with the blue prong?


You have it right.



swchang said:


> (Do lumbar settings get saved with seat memory? I don't think they do.)


No, they are not saved w/ seat memory.

I have no idea why you're experiencing this problem as I did it just about the same way as Terry did and everything works. The only difference btwn me and Terry was that I was able to get the right wire harness.


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## swchang (Oct 5, 2003)

Well, I ended up using one of each valve unit, 694 and 572, since I had spares. In those, I didn't remove the black plastic piece, and the pads inflate fine. They also deflate fine. Weird, huh? In fact, they still deflate when they reach the limit of inflation, as in they don't explode.  

I'll post some thoughts about the DIY later.


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## swchang (Oct 5, 2003)

Okay, here are my comments:

1. If you can order lumbar as part of your car, do it. You might be able to save some money if you buy the parts and install it yourself, but a lot of blood, sweat, and tears goes into it, as well as a good chunk of time. I think I spent, all together, about 6 hours or so driving to the dealership and Home Depot to buy the parts and tools, installing it, cursing a lot, and cleaning up my blood, sweat, and tears. If you don't curse much, as I usually don't, you might save yourself an extra hour.

2. In addition to this thread and Terry's DIY site (www.tmk.com/lumbar), I found some good info that pertained to my car in the following threads:
http://www.bimmerfest.com/forums/showthread.php?t=70935
http://www.bimmerfest.com/forums/showthread.php?t=69638

3. The only parts I needed were:
52-10-7-115-693 LUMBAR SUPPORT PUMP $96.25 (x 2 for both sides, x 1 for one side)
52-10-8-099-007 LORDOSIS PAD $32.75 (x 2 for both sides, x 1 for one side)
52-10-8-226-403 LEFT WIRING SET $27.75
61-31-8-352-291 LEFT SWITCH $42.00
52-10-8-226-404 RIGHT WIRING SET $27.75
61-31-8-360-877 RIGHT SWITCH $42.00
52-20-1-964-201 FRONT SEAT CLIPS $0.28 (x 4 for both sides, x 2 for one side)
07-11-9-902-007 5 MM BOLTS $0.25 (x 2 for both sides, x 1 for one side)
52-10-7-160-372 VALVE UNIT $64.50
52-10-7-115-694 VALVE UNIT $64.50

Regarding the last two items, the valve units, they're actually identical except in 372 the exhaust port faces towards the front of the car when installed and in 694 the exhaust port faces towards the rear. 372 supposedly is for sport seats and 694 for standard seats, but I don't think it actually matters a lick.

Purchasing only these parts and receiving a 20% discount for CCA membership, plus 5% MD sales tax, the total from Russel BMW should be ~$443.60.

4. I found it unnecessary to buy the seat parts kit because I took care not to break the seat backing clips when removing and replacing the seat backing. It's a reasonable investment to purchase the kit, just in case. I'd buy only one, though, because you should get enough practice from doing the first seat that you won't damage anything when doing the second one. If you're looking to save as much money as possible, like I was, just buy the 4 front seat clips. However, you actually might want to buy 8 of them, because replacing them once you've finished the install and are re-installing the seat backing is a total biotch. More on this later.

5. I also found it unnecessary to purchase the seat coverings, but if you're going to break anything in the install, this part would be it. Total pain in the arse to remove, especially the first go around, and expect to lose some skin and, potentially, blood. Having small hands/fingers really helps here, so if you're some giant with really thick fingers, force your kids to do it. If you don't have kids, have one, wait about 4 years, then have him/her do it. Like another poster said, don't be afraid to use force. However, make sure you've undone the top two and the bottom two big clips before yanking it out. Also, I recommend starting from the back, because it's easiest to undo the rear of the covering. While you're working on the front of the covering, you might hear clips snapping back into place. Take this opportunity to swear, wipe the sweat off your brow, and then undo the top clip and hold the covering out with one hand while you undo the bottom clip with your other hand. Do not worry about the middle two, smaller, bottom clips. They merely hold the electronic seat controller module into the covering.

6. Using a Dremel tool and bits, etc., may be fun. I found that a simple razor blade was sufficient. Cut around the indentation multiple times with a razor blade until you can just press the plastic piece out. You can then use the razor blade to cut remaining slivers of plastic away. I was able to get the cutout surface smooth enough with this method for my first covering piece, but I used some fine grit sandpaper on the second piece because my gf had some. Makes it a little smoother, but unnecessary if you don't have sandpaper and don't feel like buying some. Besides, like I said, it's possible to get it pretty smooth with just a razor blade and some patience, although by this point your patience may be wearing thin. If you find it therapeutic to blast away at it with a Dremel tool, feel free.

7. 401/402 is what Terry used, but I used 403/404 for my car (sports seats, electric, memory although I don't think that matters). 403/404 is completely plug and play. Four connectors, two on each end. One end has a longer plug with about 4 wires that plugs into the lumbar switch and a smaller plug that connects to the pump. The other end has a longer plug with about 5-6 wires and a smaller plug, both of which plug into the seat control module. You do not need the Bushing Contact that Terry refers to in his DIY. I suspect the 401/402 set is for manual seats. Kaz or robg can probably confirm that, but I haven't read any of their threads on this in detail since they didn't apply to my car.

8. I would not insert the wiring harness for the lumbar switch where Terry tells you to in his DIY. You probably can do it, and it'd be fine, but when replacing the seat covering and control module after the rest of the install is done, I didn't want to crush any wires. As such, I snaked that part of the wiring harness along with the wiring coming from the control module in the groove in the seat frame, then brought the connector through the hole where the lumbar switch will insert. If this part isn't entirely clear, once you've removed the seat covering and are looking at the frame, you'll understand what I mean.

9. Inserting the support pad into the seat back frame is a REAL pain in the behind. I advise you to get your tetanus boosters beforehand, because you WILL cut yourself and bleed all over your car. You will. If you don't want to visit your PMD, get some nitrile gloves or something to give yourself a modicum of defense against the razor sharp metal frame.

10. Do NOT hook the hoses up to the valve unit until the valve unit and lumbar pad are in place, because removing the hoses will be another mega pain in the patootie. If you foolishly have already done so, get a razor blade and cut the hose off right where the valve port ends, then slit the hose stub to remove it from the port. Trust me, it's much easier to do so. There's plenty of blue hose, less so but still plenty of red hose, and precious little white hose to experiment with, so try not to connect the hose to the ports for fun.

11. Terry and JoeCinVA say to remove the flimsy, thin, black rubber cap from the exhaust port on the valve unit. When I did this, I couldn't inflate the support pad when it was in place in the seat. The reason for this is when you exert pressure on the pad, and there will be constant pressure on the pad when it's installed properly, then on inflation there is concurrent deflation. I ended up not removing the rubber cap, and I was able to deflate fine when the back button was pressed, and there was much, much less, if any at all, deflation while I was inflating. I'd suggest the following: hook everything up, pad hosing, wiring harness, pump hosing, valve unit, and all while everything is not yet installed. Start to inflate the pad by using either the forward, up, or down arrow. After it's inflated at least partially (more is better, though), press the back button to deflate. The pads should not deflate unless you're exerting pressure on them (when they're not installed yet), so press down on them. If you hear air escaping and the pads deflate, you're good. Don't bother removing the black cap. If you do remove the black cap, see if you can hear air escaping from the pads while you inflate them and press down on them. If you can, you're sunk. Reinserting the black cap after you've removed it is probably possible, but a royal pain in the arse. (Have you noticed that a lot of parts of this DIY are pains in the buttocks?) BTW, don't worry about the pads exploding if you continue to inflate. They do get pretty big. And even with the black cap in place, once the pads have reached their maximum capacity, they'll release air as more air is pumped in.

12. Testing the function of the lumbar stuff before installing everything and after installing but before replacing the coverings/seat backings, as Terry suggests, is a VERY good idea. So do yourself a favor and test twice: once before installation, once after.

13. Terry says, matter of factly, at the end of his DIY to use the replacement clips to reattach the seat back. That simple imperative statement belies the frustration you will feel, as this part is really annoying, or at least it was for me. It's difficult to know if the holes are all lined up properly. My suggestion is to put the clip in partly, then feel around the seat backing after you've replaced it and try to feel the metal hole where the clip should insert. If you can feel the tip poking through there, get a hammer and gently but firmly tap it in. Using your fingers, as I was able to do for one of them, is not wise. If you must use your fingers, then if you find inserting the clip to be easy, you messed up and didn't get the clip into the metal hole. It should be quite difficult to put in. If you do mess up, you can either cut the clip back off and try again with a fresh clip, or you can painfully hammer it back out.

I think those are all my comments. If I remember anything in the future, I'll post here. Best of luck to those who undertake this exceedingly, painstakingly, frustrating task in the future. PM me if you have any questions. If you're in the Bawlmer/DC area, maybe I'll even do it for you, as long as you buy me an S2000 in return. I'd say it's well worth your money.


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## Terry Kennedy (Sep 21, 2002)

Terry Kennedy said:


> I don't know, but I've ordered a full set (401-404) and I'll report back once I get them. I'm on the road now, so don't expect anything until after July 4th.


Ok. I now have a complete set of 4 lumbar harnesses. 403/404 are definitely the correct harnesses for cars with electric seats, with or without seat memory. The connector on this harness plugs in exactly where I did my stunt with the pin contact and heat-shrink tubing. And Kaz reported that 401/402 are the correct parts for manual seats, but that the matching pins, etc. need to be installed in the car.

I'll update my web DIY accordingly.


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## G. P. Burdell (Jan 23, 2006)

I realize that this thread is nearly six years old, but I thought I'd post a few notes on my own lumbar retrofit in case there are still others who want to retrofit it to their E46.


Parts prices have risen considerably since Terry Kennedy published his DIY article. The total MSRP on all of the parts, including new seat side coverings, is now close to $850. The greatest jump in price has been for the seat parts kit, which now lists for $17.22 per side.
The lumbar support pump part number has been superseded. The new part number for standard and sport seats is 67 80 7 025 381 for cars produced from 6/2002. Be sure to confirm all of your part numbers at Penske Parts or RealOEM before ordering.
Getting the lordosis pad into the seat was definitely a test of patience. To keep the sharp edges of the seat frame from slicing up the pad and my hands, I lined all four of the lower openings with painter's tape before inserting the pad.
The lumbar support pump no longer comes with a self-adhesive strip as described in Terry's article. I applied a five-inch strip of 1" wide, adhesive-backed Velcro (the hook side) to the recess in the seat frame and then pressed the pump to it. The fuzzy bag that encloses the pump stuck readily to the Velcro.
Like swchang, I also left the black rubber plug in the valve unit exhaust port. With the plug removed, the lordosis pad would not inflate. The system works normally with the plug installed.


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## TerraPhantm (Nov 22, 2004)

For those of you who retrofitted the lumbar support - have you looked at the feasibility of retrofitting the M3-style width adjustment? Until I actually got the M3 I have now, I never realized that the width adjustment works off the same pump that the lumbar support seems to. Might be a nice upgrade for all of you non-M guys


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