# Aftermarket lumbar support options-- help me decide



## bmw325 (Dec 19, 2001)

Alright-- I've really had it with my seats (manual sport seats). My back starts hurting after about 40 minutes, and my legs go numb after about 1 hour. No amount of adjusting seems to help. I don't know what kind of stupdity causes BMW to the reserve lumbar support option for premium pkg 330s only. BMW, if you're reading this: LUMBAR SUPPORT SHOULD BE STANDARD OR ATLEAST AN A LA CARTE OPTION ON ALL OF YOUR CARS. Nearly all of your competitors do this.

Anyway, I've been doing lots of research on the options available for adding lumbar support to my seats. Here's what I've come up with:
1. Buy a lumbar roll or pad and stick it on the seat. I've tried this, but actually find them uncomfortable since they shift around, and actually stick out too much. Plus, they're just ugly.
2. Add the BMW power lumbar. 
There is a kit to do this for the e36, but a kit for the e46 hasn't been released yet. There is part number for it in the ETK, but it is not a "real" part number-- just a placeholder. Even if it was available, it probably cost around $700.
3. Add some foam to the seat to "build up" the lumbar area. This would probably be cheap to do, but I think its nice to have some sort adjustability-- a certain amount of fixed lumbar may not always be right.
4. Add a manaully adjustable mechanical-type lumbar support w/ a wheel adjustment knob. A few companies make these, but they're kind of heavy-- and require some welding to install. Would probably give the most "positive" support. Would also require cutting the seat backing to make room for the knob. This is what BMW should make standard on all of their seats-- like VW, Volvo, Mercedes and others do. In terms of feel, they're better than pretty much any inflatable system.
5. Add some sort of manaully inflatable lumbar bag w/ a "Sqeeze bulb" pump to the seats. This is the option I'm leaning towards since its cheap, easy to install, and easy to remove. Suprisingly, there aren't many options out there for this type of product. I could've sworn that BMW sold such a device-- but I can't seem to find any record of it. I would install this in between the seat springs and seat foam, and route the squeeze bulb underneath the seat, and mount it discretely (possibly near the manual tilt adjustment lever on the front of the sport seats). 
So, here's what I've come up with for option 5:
Product meant for Miata seats:
Pros:
Looks very well made, and durable
Cons:
-Looks a little small, and oddly shaped 
-Says that its specifically made for the Miata-- although I doubt that it really matters. 
http://www.miatamania.com/Shop/ViewProducts.aspx?PlateIndexID=33279&SortOrder=1

Corbeau Lumbar support
Pros:
bigger in size
Cons:
Maybe too big to properly "target" the lower back
Looks kind of flimsy
Meant for Corbeau seats--although i don't see why they cant' be used on any seat.
No mounting holes to affix it to the seat springs/support (atleast that I can see in any picture)
I'd probably just end up duck taping it to the seat supports.
http://www.ogracing.com/eshop/itemdetail.asp?ses=598muiit9fe745q1f4&itemid=127&showbrake=1
Here's a close-up pic by someone who mounted it in his WRX:
http://www.wrxfanatics.com/index.php?act=ST&f=12&t=2880&

Sparco Lumbar support
Pros
-In between the 2 sizes
-Looks fairly durable
Cons
-Pricey
-Meant to be velcroed to the surface of the seat-- not the interior. Although, I doubt it matters. -Again, no holes or flaps for attaching to the seat foam support wires.
http://www.ogracing.com/eshop/home.asp?categ=105

Which one would you choose? Right now, I'm leaning towards the Miata one or the Sparco because they look better made than the Corbeau.


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## doeboy (Sep 20, 2002)

Hmm... I got Power Lumbar but no premium pkg... I added it a la carte... :eeps: :angel:


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## JoeCinVa (Apr 26, 2002)

Don't be too quick and give up on the BMW solution. I installed the retrofit kit on my E36 and have been toying with the idea of installing it into my E46 even though there isn't a "kit" available yet. I believe I found all the parts (singly) in the ETK. They are:

Desc, Part Number, Qty, Retail $

Valve Unit, 52-10-7-004-689, 2, $64.00
Pump, 52-10-8-099-008,	2, $95.25
Pad, 52-10-8-099-007, 2, $32.50
L Wiring, 52-10-8-226-403, 1, $81.25
R Wiring, 52-10-8-226-404, 1, $81.25
L Switch, 61-31-8-352-291, 1, $41.50
R Switch, 61-31-8-360-877, 1, $41.50


The retail price for just the one side is $314.50. However, I'm unwilling to pay that much for the wiring and will try to build my own wire harness. So... excluding the wiring and if you get a 25% CCA discount for the remainder of the pieces, it's only $174.94 for a side. 

As to the wiring, my experience with the E36 install showed me how BMW did it. Basically, they used 2 connectors to tap into the hot and neg wire for the power seat, 1 connector for the new switch and one connector for the pump. 

As to the install, you could do the E36 install by just removing the seatback (but I did it removing the whole seat). If I can get a set of wiring diagrams, I'll try this retrofit in the near future and will try to do it with the seat still in the car.


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## bmw325 (Dec 19, 2001)

JoeCinVa said:


> Don't be too quick and give up on the BMW solution. I installed the retrofit kit on my E36 and have been toying with the idea of installing it into my E46 even though there isn't a "kit" available yet. I believe I found all the parts (singly) in the ETK. They are:
> 
> Desc, Part Number, Qty, Retail $
> 
> ...


Very cool! Thanks for the info. I've read some accounts of installing the lumbar in e36 M3s. I wonder if I'd have to run new wires since I have manual seats-- I do have heated seats though.


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## JoeCinVa (Apr 26, 2002)

For those that are still interested in adding this feature, here is the wiring diagram, component locations and connector diagrams for the driver's lumbar seat. FWIW, I found that the Bentley's schematics aren't all that inclusive. I ended up finding and stitching multiple screen shots together from bmwtis.com.

I'm still working on identifying the p/n for the connectors. I think I know what they are though.

Anyone want to take it from here?


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## EdCT (Mar 14, 2002)

robg said:


> Alright-- I've really had it with my seats .


Hi Rob,

Have you looked into actually replacing the entire seat with one of those really nice comfy jobs?

I'm not up on seats these days, but some one must be making a nice seat replacement for E46's.

(btw, 5 series seats seem really comfortable to me, I wish there was more consistency across the line re seats).

Ed


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## Terry Kennedy (Sep 21, 2002)

JoeCinVa said:


> Anyone want to take it from here?


I'm giving it serious thought. However, I'm coming up with different part numbers and I'd appreciate your input.

First, I get different part numbers for the valve unit and pump, possibly becase my car is an 09/02 production and this apparently changed at 06/02:

Valve unit: 52 10 7 115 694
Pump: 52 10 7 115 693

Next, I get different part numbers for the L and R harnesses - the ... 403 and ... 404 claim to be for seats without memory, while ... 401 and ... 402 are for seats with memory. All 4 parts come up without a price in the ETK, though (which isn't a guarantee of anything as the US dealer system doesn't use ETK pricing).

Lastly, the switch part numbers you list - 61 31 8 352 291 and 61 31 8 360 877 - show up as only applicable to the 7 and 5 series. Were you able to confirm that these switches are the right ones for the 3 series as well?


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## racerdave (Sep 15, 2003)

doeboy said:


> Hmm... I got Power Lumbar but no premium pkg... I added it a la carte... :eeps: :angel:


So since it *is* possible to get Power Lumbar (although a special order), what do you think of it?

Does it make a difference?

I've been kicking around the idea of trying to do the special order or not...


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## doeboy (Sep 20, 2002)

racerdave said:


> So since it *is* possible to get Power Lumbar (although a special order), what do you think of it?
> 
> Does it make a difference?
> 
> I've been kicking around the idea of trying to do the special order or not...


It's sort of extra insurance incase I ever need it. Generally the seats feel fine, but over long drives having that extra support is nice if I ever need it. It was a little expensive but I have no regrets about ordering it.

If you don't get it, I believe it is possible to retrofit the lumbar into your seats, but I don't know how much that would cost. Also it's easier to just get the car with it than having to rip your seats out and put those in later IMO.


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## bmw325 (Dec 19, 2001)

I would definitely recommend special ordering it. The seats are lacking in lumbar support-- and you WILL need it on longer trips. Its a bit expensive-- but it'll be much more of a pain to try and retrofit it later. The biggest mistake I made when ordering my car was that I forgot to ask to special order the lumbar.


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## JoeCinVa (Apr 26, 2002)

I ordered (but have not installed yet) most of the parts (driver side only) and pics are below.


Terry Kennedy said:


> First, I get different part numbers for the valve unit and pump, possibly becase my car is an 09/02 production and this apparently changed at 06/02: Valve unit: 52 10 7 115 694, Pump: 52 10 7 115 693


 Can't tell you about your 9/02 car because my ETK goes only to 2/02 but I can't understand why the p/n would be different (unless superceded) if it's the same seat structure. FYI, I ordered my listed p/n about a month ago, so those p/n are still in the "system".



Terry Kennedy said:


> Next, I get different part numbers for the L and R harnesses - the ... 403 and ... 404 claim to be for seats without memory, while ... 401 and ... 402 are for seats with memory.


 Refering to ETK diagram 61-1220. I don't get any differentiation with regard to memory or not. What I do get is that 403 and 404 are for seats with Electric Seats while 401 and 402 are for seats without electric seats. I don't believe memory or not matters because the lumbar position is not memorized. The difference btwn the 2 sets of wires is that electric seats allow you to tap into it's electric module (module A21) for power and ground whereas not having electric seats would require the 401 and 402 harness to be routed somewhere else for power and ground.



Terry Kennedy said:


> Lastly, the switch part numbers you list - 61 31 8 352 291 and 61 31 8 360 877 - show up as only applicable to the 7 and 5 series. Were you able to confirm that these switches are the right ones for the 3 series as well?


 Those part numbers show up correctly in ETK diagram 61-1272 (325xiT, 2/2002). Plus, see the pic of the switch below.

Some comments on the pics/retrofit.
1) I'm pretty sure you don't have to take the seats out of the car. See the trim piece I bought below (less that $10). You have to unscrew (one screw) and unsnap it off your seat (can be done in car). You don't have to buy this piece, but I chose to so that I can see where the mounting tabs are, pre-cut the hole (I don't have a garage), plus it's cheap. Cut the hole out for the switch and the switch will snap into place. The only other piece you have to get out is the seatback.

2) The pad has two color coded tubes. Red and Blue.

3) The valve has 2 colored and 1 non-colored air "pips". Red and Blue go to the pad. The non-colored "pip" go to the pump.

4) I'm electing to build the harness myself (cheaper). The harness only has 3 connectors:

a) Pump Connector: 3 pin black female housing with 2 male pins.
1 x Female Socket Housing, 3 Pol, 61-13-8-377-213
1 x Female Socket Housing Cap, 3 Pol, 61-13-1-383-552
2 x Male Pin Contact (AMP), 0.2-0.5 mm2, 61-13-0-005-198

b) Valve Connector: 6 pin black male housing with 4 female pins.
1 x Male Socket Housing, 6 Pol, 61-13-6-909-058
1 x Male Socket Housing Cap, 6 Pol, 61-13-1-383-816
4 x Female Bushing Contact (AMP), 0.2-0.5 mm2, 61-13-0-005-197

c) Switch: 6 pin black male housing with 6 female pins.
1 x Male Socket Housing, 6 Pol, 61-13-6-909-058
1 x Male Socket Housing Cap, 6 Pol, 61-13-1-383-816
6 x Female Bushing Contact (AMP), 0.2-0.5 mm2, 61-13-0-005-197

d) 2 loose contacts that plug into the electric seat module connector for power and ground that are either the 197 female or 198 male. Don't know but my guess is that they're female.

I have all the parts except the 6 pol male socket housing/cap (they're on order/ I ordered the female housing by mistake). Total MSRP cost for driver's side only (w/o harness and trim piece but w/ everything listed in para 4) is around $240. Less than $200 with CCA/shopping around.

Good Luck.

Good Luck.


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## bmw325 (Dec 19, 2001)

JoeCinVa said:


> I ordered (but have not installed yet) most of the parts (driver side only) and pics are below.
> Can't tell you about your 9/02 car because my ETK goes only to 2/02 but I can't understand why the p/n would be different (unless superceded) if it's the same seat structure. FYI, I ordered my listed p/n about a month ago, so those p/n are still in the "system".
> 
> Refering to ETK diagram 61-1220. I don't get any differentiation with regard to memory or not. What I do get is that 403 and 404 are for seats with Electric Seats while 401 and 402 are for seats without electric seats. I don't believe memory or not matters because the lumbar position is not memorized. The difference btwn the 2 sets of wires is that electric seats allow you to tap into it's electric module (module A21) for power and ground whereas not having electric seats would require the 401 and 402 harness to be routed somewhere else for power and ground.
> ...


Very interesting-- this is the most information I've seen to date on retrofititng electric lumbar. QUestion-- I have manual sport seats w/ seat heaters-- would I be able to tap into the power/ground for the seat heaters to drive the lumbar? Or would that be a bad idea? For non-powered seats, what is the correct way-- are you supposed to run wires the fuse box? What fuse does the lumbar use?

Also, do you have any instructions on how to install the pump unit?


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## racerdave (Sep 15, 2003)

Thanks Rob and Doeboy... I was originally planning on getting the OBC... until I found out how easy it is to retrofit, particularly because I'm going to do the M3 wheel the day I get the car anyway.

So since I'm deleting the 300 for OBC, I can add the 450 for lumbar and not be too far off my original price point.

Thanks!


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## Terry Kennedy (Sep 21, 2002)

JoeCinVa said:


> Can't tell you about your 9/02 car because my ETK goes only to 2/02 but I can't understand why the p/n would be different (unless superceded) if it's the same seat structure. FYI, I ordered my listed p/n about a month ago, so those p/n are still in the "system".


See the attached ETK capture which shows different parts for before and after 06/02. This is from an 09/03 ETK.


> Refering to ETK diagram 61-1220. I don't get any differentiation with regard to memory or not. What I do get is that 403 and 404 are for seats with Electric Seats while 401 and 402 are for seats without electric seats.


Take a look at the second attachment, which shows 401/402 for "EL. FRONT SEAT ADJUSTMENT W. MEMORY" vs. 403/404 for "ELECTR. FRONT SEAT ADJUSTMENT".


> Those part numbers show up correctly in ETK diagram 61-1272 (325xiT, 2/2002). Plus, see the pic of the switch below.


My 09/03 ETK doesn't even show a diagram 61_1272 for a 325xiT, 2/2002. I'll have to reinstall an older ETK and see if it shows up there.

Thanks for the additional info! Do the pump and pad come with all the necessary tubing?


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## JoeCinVa (Apr 26, 2002)

1) Robg- 

I'm sorry but I don't know exactly how the lumbar wiring works for non-electric seats. I found the lumbar w/ electric seats wiring diagram on bmwtis.com. If you're interested, sign up for the $20 day subscription and find out. 

If you don't want to do that, then here are my thoughts. Personally, I wouldn't tap into the seat heating wires. I would just run it to the fuse box in the glove compartment and tap into the correct fuse. Speaking of which, I also do not know what fuse number it is but I am certain that the listing in the fuse box will have the information.

Ref physically mounting the pump and valve unit. The pump is just zip tied in position. The valve unit has a female screw receptacle on it so I anticpate there being some attachment point in the seat frame. If not, then I'll just zip tie this also. 

2) Terry-

I don't know what else to say about the p/n's. Since the lumbar position isn't memorized the only inputs/outputs needed to enter the lumbar "system" is + and - and therefore as long as you get a matching group of parts (either the ones I ordered or what you dug up), it should work. 

Yes, the pump and pad come with all necessry tubing. The pad comes with the red and blue tube already attached. The pump comes with a clear tube attached. All 3 tubes plug into the valve unit which is color coded. BTW, the valve unit controls an upper and lower air chamber in the pad which is unlike the single chamber pad I have on my E36.

OT: just got a Phatbox and am installing it into the E36. Can't wait to try out the PhatVoice. Thanks for the work.

3) Hope this helps. Good Luck.


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## bmw325 (Dec 19, 2001)

Thanks for your input, Joe. I'll sign up for the day subscription-- its certainly worth the $20 (I've done it once before just to peruse and download lots of pdfs). Do they have a document on BMWtis that describes all the fuse assignments for every possible accessory? Surprisingly, I could never find that (I looked when i signed up before)-- although it seems like a piece of info they would have.

Thanks for all of your informative posts (you too Terry). Although I've installed a manual inflatable lumbar that has gotten me past my initial seat comfort problems-- my OCD nature has me wanting to install the correct "factory" lumbar. Although-- if I confirm that I have to run wires all the way to the fuse box, the "PITA" factor will probably outweight the "ocd" factor , and i'll just live w/ my manual 2-way lumbar  This would be my first wiring project--so I'm a little nervous--I need to learn how to read those wiring diagrams properly. :eeps:

When do you plan to actually install these parts in your car, btw?



JoeCinVa said:


> 1) Robg-
> 
> I'm sorry but I don't know exactly how the lumbar wiring works for non-electric seats. I found the lumbar w/ electric seats wiring diagram on bmwtis.com. If you're interested, sign up for the $20 day subscription and find out.
> 
> ...


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## NickACS (Jun 7, 2003)

Hi Rob-
I am looking to sell my OEM Sport/Premium black leather seats from my '01 330i. I am swapping them out for aftermarket seats or E46 M3 ones.
If your interested at all, just email/PM me here 

Thanks and good luck!


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## bmw325 (Dec 19, 2001)

Joe-

I looked at the wiring diagrams-- looks like I have to see if pin 13 of the yellow connector under the seat is active-- that would be the pin that would supply power (via fuse 65 for the driver's side-- at 30amps) to the lumbar and/or power seats (if I had them). since my car didn't come with power seats or lumbar, I have a bad feeling that its missing this wire. Pin 14 is the ground (which I would have).

Nick-- I actually prefer the manual seat adjustmets-- and only really want the lumbar. If you'd consider "parting out" the lumbar components in the driver's seat for a reasonable price-- I guess I'd consider that-- but I bet you probably don't want to do that. 

Regardless, if doing this project would mean that I'd have to run a new wire to the fuse box (which I will unless by some miracle my car is pre-wired and pin 13 is hot), I probably won't go through w/ it.

I wonder if I could rig it up to run off of some sort of small battery ( since I wouldn't adjust it very much)?


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## NickACS (Jun 7, 2003)

Hi Rob,
Yea, sorry I wouldn't want to part out the lumbar support  But good luck on your project! I'm sure you'll end up with what you want.. 
Take care,
Nick


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## JoeCinVa (Apr 26, 2002)

robg said:


> Although-- if I confirm that I have to run wires all the way to the fuse box, the "PITA" factor will probably outweight the "ocd" factor , and i'll just live w/ my manual 2-way lumbar  This would be my first wiring project--so I'm a little nervous--I need to learn how to read those wiring diagrams properly.
> 
> When do you plan to actually install these parts in your car, btw?


Rob,

Don't be discouraged at running wires to the fusebox. If you think about it, this is really a good project to start off with wiring. You're only running 2 wires (if you're doing only one seat). Given the proper electrical tools, this is actually pretty easy. Let me know if I can help. BTW, I don't plan on doing this install for a couple of months. I've still got to finish off a couple of mods I'm doing to my E36. Good Luck.


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## bmw325 (Dec 19, 2001)

JoeCinVa said:


> Rob,
> 
> Don't be discouraged at running wires to the fusebox. If you think about it, this is really a good project to start off with wiring. You're only running 2 wires (if you're doing only one seat). Given the proper electrical tools, this is actually pretty easy. Let me know if I can help. BTW, I don't plan on doing this install for a couple of months. I've still got to finish off a couple of mods I'm doing to my E36. Good Luck.


Thanks for the encouragement. When I think about it-- I guess its not the wiring aspect per se that would be the pain-- rather, it would be the pain of having to diassemble a lot of things to be able to propeperly run the wire from the seat to the fusebox. I assume to do it properly, I'd probably want to bundle the wire along the existing wires that go in the connector under the seat-which probably means untaping the mass of wires, adding mine and then retaping. Then, i'd have to remove the seats, the carpeting, the center console, the glovebox, the fusebox (and maybe more that I'm not thinkng of). Or is there some trick to running the wire to the fusebox without having to remove all that stuff? Also, you said 2 wires--but wouldn't it just be 1 wire (the power one) since the ground wire is already "hooked up" to the right pin on the seat connector? Just asking to make sure i'm not missing something.

QUestion on reading the wiring diagram--so if I look at the lumabr3.jpg diagram (for example), do the numbers (1,2,3,4,5,etc) next to the lines refer to the pin number on the connector? That's what they appear to be-- but just checking... I got confused-- because when I was looking at another diagram on BMWTIS.com, one of the numbers was 28- on a connector that only had 25 pins.


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## Kaz (Dec 21, 2001)

Wah, I haven't been keeping up with this project, and now I'm a little overwhelmed. I don't know how everyone else managed it, but I couldn't get the PNs for any of those parts out of the ETK (mine is 04/03). The info on the wiring and tubing , mounting, etc. are as I've suspected to date. I'm definitely interested in putting this in when it's all figured out, or even make some contributions if I can.

As for seat removal, I've done it in my car when I tried fitting the Vader, and it's actually not that tough. Now, my manual seats were actually lighter than the manual Vader seats, so they weren't much of a bear to handle.


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## Terry Kennedy (Sep 21, 2002)

Kaz said:


> Wah, I haven't been keeping up with this project, and now I'm a little overwhelmed. I don't know how everyone else managed it, but I couldn't get the PNs for any of those parts out of the ETK (mine is 04/03). The info on the wiring and tubing , mounting, etc. are as I've suspected to date. I'm definitely interested in putting this in when it's all figured out, or even make some contributions if I can.


Well, I ordered the complete kit of parts today (everything but the passenger harness should be in on Monday; the harness will take a bit longer) so I'll probably put together a full DIY like I did for my illuminated cupholder project. Of course, if I have any questions I'll be posting here...

In the 09/03 ETK, the parts are all there, except for the switch. They're on two diagrams - one for the seat harnesses in electrical, and one for the rest of the parts in seating.


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## Kaz (Dec 21, 2001)

Terry Kennedy said:


> In the 09/03 ETK, the parts are all there, except for the switch. They're on two diagrams - one for the seat harnesses in electrical, and one for the rest of the parts in seating.


OK, I found the PNs for the pump, valve and airbag. Has the PN for the switch actually been determined? I couldn't find it in the X5 (which uses the same mech) section either.


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## Terry Kennedy (Sep 21, 2002)

Kaz said:


> OK, I found the PNs for the pump, valve and airbag. Has the PN for the switch actually been determined? I couldn't find it in the X5 (which uses the same mech) section either.


According to JoeCinVa, it shows up in his 02/02 ETK. My 09/03 ETK only shows that part number as applying to various 5 and 7 series.


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## JoeCinVa (Apr 26, 2002)

robg said:


> Also, you said 2 wires--but wouldn't it just be 1 wire (the power one) since the ground wire is already "hooked up" to the right pin on the seat connector? Just asking to make sure i'm not missing something.
> 
> QUestion on reading the wiring diagram--so if I look at the lumabr3.jpg diagram (for example), do the numbers (1,2,3,4,5,etc) next to the lines refer to the pin number on the connector? That's what they appear to be-- but just checking... I got confused-- because when I was looking at another diagram on BMWTIS.com, one of the numbers was 28- on a connector that only had 25 pins.


Rob,
You're right, it would only be one wire (+) if the ground is already under the seat. Also, I did not fully appreciate the difficulty in running the wire underneath the carpet to the fusebox. Yes, that would suck. In that case, I would just tap into the seat heating power and ground underneath your seat.

Regarding the wiring diagrams- Yes, the numbers next to the lines refer to the pin numbers on the connector. Note that there is a connector reference number in the form of X followed by a bunch of numbers. That uniquely identifies the connector in the car. Other numbers/characters next to the "lines" in the diagram refer to wire thickness (in mm2 as opposed to gauge) and wire color (abbreviated german). Ron Stygar has a good write up on these two issues on unofficialbmw.com.


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## bmw325 (Dec 19, 2001)

JoeCinVa said:


> Rob,
> You're right, it would only be one wire (+) if the ground is already under the seat. Also, I did not fully appreciate the difficulty in running the wire underneath the carpet to the fusebox. Yes, that would suck. In that case, I would just tap into the seat heating power and ground underneath your seat.
> 
> Regarding the wiring diagrams- Yes, the numbers next to the lines refer to the pin numbers on the connector. Note that there is a connector reference number in the form of X followed by a bunch of numbers. That uniquely identifies the connector in the car. Other numbers/characters next to the "lines" in the diagram refer to wire thickness (in mm2 as opposed to gauge) and wire color (abbreviated german). Ron Stygar has a good write up on these two issues on unofficialbmw.com.


Thanks! I'll have to check out Ron's write up and on how to read the diagrams. Unfortunatley, it doesn't look like tapping the seat heating power wire would be a good idea-- according to the diagrams I looked at, its hooked up to a 7.5A fuse, as opposed to the 30A fuse that would e used for the power seats/lumbar. Of course, that fuse is meant to be able to support a circuit capable of handling power seats + lumbar. If I was just driving the lumbar-- maybe the 7.5A would be enough. Worst case, if I tried this and it didn't work, I'd just blow the fuse, right? Or, I'd find out that the power line for the heated seat is only "hot" when the seat heater is switched on-- which would mena the lumbar woud only work w/ the heated seat switched (although I could live w/ that sort of hack if it worked). Thanks for taking the time to share your thoughts with me-- i'm learning a lot as I think this through.

One ohter question I keep meaning to ask-- what do those type codes mean-- the ones in that chart you posted that shows what each pin on connector 652 is. THere''s a type column with "A", "E" and "M" being the various types.


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## JoeCinVa (Apr 26, 2002)

robg said:


> One ohter question I keep meaning to ask-- what do those type codes mean-- the ones in that chart you posted that shows what each pin on connector 652 is. THere''s a type column with "A", "E" and "M" being the various types.


E= Input, A= Outpout, M= Ground. Why not I, O & G- probably E,A,M are the german abbreviations.

I'll have to think about your other question. Too early right now.


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## bmw325 (Dec 19, 2001)

JoeCinVa said:


> E= Input, A= Outpout, M= Ground. Why not I, O & G- probably E,A,M are the german abbreviations.
> 
> I'll have to think about your other question. Too early right now.


Thanks for being such a good sport w/ my endless newbie wiring questions. A related question to my fuse question (a little knowlegde is a dangerous thing)...
So, the wiring diagrams specify the thickness of wiring used in mm2. What are the implications of connecting a wire of a greater thickness w/ one of a smaller thickness? TO give a specific example:
if the power wire that runs the heated seats (the one that I would "splice" into) is thinner/thicker than the power line that runs from the lumbar switch--what would the consequences be? 
My guess is that since its a 7.5A circuit w/ a fuse-- the fuse would blow before the wiring ever got too hot. OTOH, if i were to use undersized wiring on a larger circuit-- the wiring could get too hot or catch on fire. DOes that sound correct? In my case, I think the wire from the lumbar switch to the power line for the heated seats would actually be "oversized" for that circuit (since it will be sized to be used on a 30A circuit)-- which wouldn't hurt anything I guess? Are there any tricks for splciig/connecting 2 different wiring sizes?

One other thing related to the splicing/connceting: If I were to use the heated seat power line, my "fantasy" would be to do it without cutting any existing wiring. I'm imagining creating a little "Sandwich" connecotr that would go in between the harness connector from the floor and the connector on the seat. This connector would just be a simple female on 1 end/male on the other-- but would have a wire leading out the side (possibly) that would "steal" the juice from the power line. Don't know how hard/possible/insane something like that would be to create. Or, are there other simpler ways of tapping into existing wiring without cutting the wires (or atleast doing something that can't be easily returned to stock form).

I've done a lot of searches on the web--- but much of what I read seems to overlook stuff like fuse ratings and wire sizes-- people seem to just tap into "hot" lines w/ wild abandon---the biggest issue people discuss w/ auto wiring is finding switched or unswitched power---but most of the wiring projects i read about involved lower power stuff like lighted shift knobs and radar detectors.


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## Terry Kennedy (Sep 21, 2002)

robg said:


> So, the wiring diagrams specify the thickness of wiring used in mm2. What are the implications of connecting a wire of a greater thickness w/ one of a smaller thickness?


You can always use a heavier (bigger) wire to tap, up until the point where the wire becomes too big to fit in the connector or splice you're using. You will still only be able to safely pull the amount of power that the thinner wire can support, so the larger wire is overkill. Really, the only reason to use it is because you have it around and you're in a rush, or if it is permanently attached to the item you're connecting.


> My guess is that since its a 7.5A circuit w/ a fuse-- the fuse would blow before the wiring ever got too hot. OTOH, if i were to use undersized wiring on a larger circuit-- the wiring could get too hot or catch on fire. DOes that sound correct?


You have to be careful, as BMW sometimes uses wire that is too small for a fuse because the fuse supplies power to a number of other things, and the individual devices have fuses. The classic example is the CD changer, which is on a rather large fuse with a skinny wire, and the changer itself has a 3A fuse on the back of its case. That's why you may have read stories about "my [insert brand here] CD adapter burned up my wiring harness".

If you want to wait a bit until I've done my retrofit, then you can look at my DIY for the mechanical stuff (since I have power seats, the electrical won't apply directly) and I'd be glad to visit and help with your install (I can bring my collection of BMW parts and tools, as long as you have a heated garage ).


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## bmw325 (Dec 19, 2001)

Terry Kennedy said:


> You can always use a heavier (bigger) wire to tap, up until the point where the wire becomes too big to fit in the connector or splice you're using. You will still only be able to safely pull the amount of power that the thinner wire can support, so the larger wire is overkill. Really, the only reason to use it is because you have it around and you're in a rush, or if it is permanently attached to the item you're connecting.
> You have to be careful, as BMW sometimes uses wire that is too small for a fuse because the fuse supplies power to a number of other things, and the individual devices have fuses. The classic example is the CD changer, which is on a rather large fuse with a skinny wire, and the changer itself has a 3A fuse on the back of its case. That's why you may have read stories about "my [insert brand here] CD adapter burned up my wiring harness".
> 
> If you want to wait a bit until I've done my retrofit, then you can look at my DIY for the mechanical stuff (since I have power seats, the electrical won't apply directly) and I'd be glad to visit and help with your install (I can bring my collection of BMW parts and tools, as long as you have a heated garage ).


Thanks for the offer Terry-- i just might take you up on it. I'm in no hurry to do this-- i'm just "amassing information" now. I'll try and do some research to see if the heated seat itself has some sort of fuse-- but from what i've read-- I don't think so. What is your "gut feeling" on whether tapping into the power line for the heated seats to drive the lumbar motor would work? The lumbar would typicall be driven off a 30A fuse-- but that's only becasue it uses the same fuse as the whole power dirver's seat. Also, i couldn't figure this out from the wiriding diagram for the heated seats-- but hwat is your sense for how they work? Scnerario 1:
The power line to the seat always be hot-- and when you press the heated seat button, the central swithc console controller sends a bus signal over another line to a controller in the heated seats that causes the seat to start drawing power, and cycling its use of poewr to maintain the temp. Since there are multiple levels of seat heating, and its thermostatically controlled-- I think this contorl might happen within the seat itself.
Scnerario 2:
when you press the heated seat button, the central switch console "turns on" the power line to the heated seat. The heated seat continues to warm until a feedback signal from a thermostat in the seat tells it that its reached the desired temp. It then cycles power on and off to maintain the temp.

The main difference is whether the heated seat itself "chooses' to draw power or not-- or whethe th ecentral switch console just turns the poewr line on and off w/ the aid of a feedback signal from the seats. I'm guessing its scenario 2 (which would be bad since it would mean that the heated seat would have to be on to get the power line hot). AS a second question, ON the wiring diagrams, how are bus (signal) lines denoted (as opposed to straight power or ground lines)?

I have a faint hope that the wiring harness to the seat already includes the power line for the power seat/lumbar-- and that just by adding fuse 65, I can "enable" it. I doubt it though.

Is there a way to find out how many Amps just the lumbar components need in order to run?

Will the wiring diagrams indicate when a device is supposed to have its own fuse?

The more I think about this, the mroe questions I have-- but I'm really having fun learning about this stuff!


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## Terry Kennedy (Sep 21, 2002)

robg said:


> I'll try and do some research to see if the heated seat itself has some sort of fuse-- but from what i've read-- I don't think so. What is your "gut feeling" on whether tapping into the power line for the heated seats to drive the lumbar motor would work? The lumbar would typicall be driven off a 30A fuse-- but that's only becasue it uses the same fuse as the whole power dirver's seat.


Once I receive the parts, I'll look at the motor. Chances are it has a plate with the rating on it, which is likely to be a lot less than 30A.


> Also, i couldn't figure this out from the wiriding diagram for the heated seats-- but hwat is your sense for how they work? Scnerario 1:
> The power line to the seat always be hot-- and when you press the heated seat button, the central swithc console controller sends a bus signal over another line to a controller in the heated seats that causes the seat to start drawing power, and cycling its use of poewr to maintain the temp. Since there are multiple levels of seat heating, and its thermostatically controlled-- I think this contorl might happen within the seat itself.


I don't know. Given the 3 levels of heat selectable from the button on the switch panel, there might be several power lines from that switch to the seat (minimum of 2, for heat levels A, B, and A+B) or there might be a resistor in the switch panel. I think JoeCinVa has/had a TIS account and might have the wiring diagram.


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## bmw325 (Dec 19, 2001)

Terry Kennedy said:


> Once I receive the parts, I'll look at the motor. Chances are it has a plate with the rating on it, which is likely to be a lot less than 30A.
> I don't know. Given the 3 levels of heat selectable from the button on the switch panel, there might be several power lines from that switch to the seat (minimum of 2, for heat levels A, B, and A+B) or there might be a resistor in the switch panel. I think JoeCinVa has/had a TIS account and might have the wiring diagram.


Thanks Terry. I just remembered that Joe has already purchased the parts. Joe-- if you're still listening, could you look at the motor and see if it says what its power rating is?


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## JoeCinVa (Apr 26, 2002)

Rob,
Sorry I've been away for awhile. Some answers to your questions/thoughts:
1) The pump that I have has a marking on it that says 15A/13.5V DC. Also, as to wiring sizes and fuses, I concur with everything Terry has to say but have this thought to add: this is just for a lumbar motor. This motor is on how long at any give time? Ten seconds? 

2) I'm sorry but I don't have a wiring diagram for the non-powered seats. I only subscribed to BMWTIS.comfor one day and just have the one diagram I posted above.

3) I can't say which scenario the power to your heated seats are, i.e. 

"The main difference is whether the heated seat itself "chooses' to draw power or not-- or whethe th ecentral switch console just turns the poewr line on and off w/ the aid of a feedback signal from the seats. I'm guessing its scenario 2 (which would be bad since it would mean that the heated seat would have to be on to get the power line hot). "

However, the wiring diagrams for the E36 heated seats are as your second scenario describes and I suspect it's the same with the E46.

4) Given all this, as painful as it sounds it may be best to do it the right way and just rip out the driver's seat and run the wires. Maybe you could tack on additional projects to make ripping out the interior worthwhile such as rear fogs and power sunshade.

Hope this helps. Good Luck.


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## Terry Kennedy (Sep 21, 2002)

JoeCinVa said:


> Hope this helps. Good Luck.


I've started writing up my DIY for this (for cars with power seats with memory). You can find it here. Right now it is only up to the point where I modified the plastic side panels to hold the switch, as the wiring harnesses are on national backorder at the moment and are coming from Germany.


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## bmw325 (Dec 19, 2001)

JoeCinVa said:


> Rob,
> Sorry I've been away for awhile. Some answers to your questions/thoughts:
> 1) The pump that I have has a marking on it that says 15A/13.5V DC. Also, as to wiring sizes and fuses, I concur with everything Terry has to say but have this thought to add: this is just for a lumbar motor. This motor is on how long at any give time? Ten seconds?
> 
> ...


Thanks for the info Joe. I had the same thought about the lumbar motor only being used for a few seconds at a time. I'm still deciding whether I want to rip out the whole interior for this-- probably not.


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## bmw325 (Dec 19, 2001)

Terry Kennedy said:


> I've started writing up my DIY for this (for cars with power seats with memory). You can find it here. Right now it is only up to the point where I modified the plastic side panels to hold the switch, as the wiring harnesses are on national backorder at the moment and are coming from Germany.


Cool! So you're going to do both seats, or just the driver's?


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## Terry Kennedy (Sep 21, 2002)

robg said:


> Cool! So you're going to do both seats, or just the driver's?


Both. That way I can practice on the passenger seat and still be able to drive the car to get any additional parts I need . I already found that removing the seat back requires a replacement set of fasteners to put it back together (the TIS instructions start with "cut the clips...").


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## bmw325 (Dec 19, 2001)

Terry Kennedy said:


> Both. That way I can practice on the passenger seat and still be able to drive the car to get any additional parts I need . I already found that removing the seat back requires a replacement set of fasteners to put it back together (the TIS instructions start with "cut the clips...").


Yes-- in fact I have removed the driver's seatback in car to install my current manual lumbar support. I have the part number for the set of replacement clips you need (they come in a bag w/ some other seat-related clips that you don't need). Tell me what method you use to get those clips out. I kind of scuffed up the bottom of the panel w/ my "methods". Basically, I used a screwdriver to pry the pins out enough so that i could get a small serrated knife in there to saw off the pins. I'd like to know the proper, "non ham-fisted" way to do it. :tsk:


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## Terry Kennedy (Sep 21, 2002)

robg said:


> Tell me what method you use to get those clips out. I kind of scuffed up the bottom of the panel w/ my "methods". Basically, I used a screwdriver to pry the pins out enough so that i could get a small serrated knife in there to saw off the pins. I'd like to know the proper, "non ham-fisted" way to do it. :tsk:


Take a look at the TIS document for it - it suggests "Side cutting pliers" - PDF here.


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## bmw325 (Dec 19, 2001)

Terry-

I did look at that before I started. But the heads of the push clips in question are basically flush w/ the underside of the seatback panel. So, in order to use any sort of cutting tool, it seemed to me that I had to pry out the pins to the point where I could get a cutting instrument in there. Side cutting pliers (atleast the ones I've seen), are fairly bulky-- so you'd have to pry out the pin quite a bt to have a chance of using them. I used several differnt types of screwdrivers, and spent about 20 minutes-- and could only get the pin pried out a little bit-- it starts to bend and its quite firmly inserted so I could only get it out far enough to get the blade of a thin serrated knife between the clip head and the panel. At that point, I was so frustrated that I just sawed away-- but ended up scuffing and sort tearing up the vinyl on the bottom of the panel. Now, I'm pretty bad at this sort of thing (i've had trouble w/ nearly every interior-related project on my car--especially when it comes to removing plastic compoents w/o breaking, scratching or scuffing something)-- so I'm sure there's a better way, and the "right" tool-- I'm interested to find out what method you end up using.

I'm especially interested in this because I also bunged up the re-installation, and ended up inserting the new push-pin through the hole in the bottom of the panell--- but the panel wasn't firmly flush against the back of the seat, so the pin ended up missing the metal grommet that its supposed to go into. To fix it, I have to remove the pin again--but I dread doing it until I learn an easier more "proper" way. 

NEver thought I could write this much about a lousy plastic clip-- but godammit-- those clips drove me crazy. 

This experience also sort of scared me away from the prospect of taking apart my whole interior to run the power line from the seat to the fusebox to drive the lumbar pump motor. I'm sure there's lots other nasty stuff that I'll never be able to put back together properly.


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## Terry Kennedy (Sep 21, 2002)

robg said:


> I'm especially interested in this because I also bunged up the re-installation, and ended up inserting the new push-pin through the hole in the bottom of the panell--- but the panel wasn't firmly flush against the back of the seat, so the pin ended up missing the metal grommet that its supposed to go into. To fix it, I have to remove the pin again--but I dread doing it until I learn an easier more "proper" way.
> 
> NEver thought I could write this much about a lousy plastic clip-- but godammit-- those clips drove me crazy.
> 
> This experience also sort of scared me away from the prospect of taking apart my whole interior to run the power line from the seat to the fusebox to drive the lumbar pump motor. I'm sure there's lots other nasty stuff that I'll never be able to put back together properly


I think that these pins are the single-use ones which have a bunch of fins / ribs sticking out from a central shaft. Sort of like the ones in the bottom right compartment of the attached picture, but without the large head. It should be possible to just grab the head of the pin with some pliers and give it a good pull to get it out. I haven't taken my seats apart yet or picked up the kit with the pins in it (it should be at the dealer on Friday).

BMW uses a wide variety of plastic fasteners - aside from these finned pins (which also show up inside the doors as cable clips) there are re-usable ones of the same general style (for example, in the door sills), ones with a center pin that makes them expand (under the steering wheel trim) and ones with a plastic screw that expands them (in the center console, under the rear ashtray).

I wouldn't let this scare you away - just have a copy of the TIS that applies to your car so you have all the proper procedures at hand. It also helps to have a box of miscellaneous parts, like this:










Once I get mine done, I'd be glad to help you with yours (you're not too far from the NYC area as I recall).


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## bmw325 (Dec 19, 2001)

These pins are a bit nastier since they have ribs that are sort of wedge shaped-- which makes them easy to push in, but very hard to pull out. ALso, this particular pin has a gap the middle w/ no ribs-- so that when its fully inserted, the gap is inside teh metal grommet, and there are ribs above and below the gromet. Also, the heard of the pin is very thin and rouded + its flush w/ the bottom of the seat so I couldn't figure out how to get any sort of grip on it w/ any pliers. That's why I ended up just prying out a little w/ a screwdriver (although even that was hard) and then sawing it w/ a thin knife. I guess if you have a pair of pliers w/ a really thin set of blades, it might be possible to do it all in one step as the TIS document suggests. I do have the TIS-- and have had it at hand before-- but for some reason it generally seems to lack the crucial details I need to be able to properly execute the job--especially when it comes to interior trim. LIke I said, I'm pretty ham-fisted w/ this stuff.


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## Terry Kennedy (Sep 21, 2002)

robg said:


> These pins are a bit nastier since they have ribs that are sort of wedge shaped-- which makes them easy to push in, but very hard to pull out. ALso, this particular pin has a gap the middle w/ no ribs-- so that when its fully inserted, the gap is inside teh metal grommet, and there are ribs above and below the gromet. Also, the heard of the pin is very thin and rouded + its flush w/ the bottom of the seat so I couldn't figure out how to get any sort of grip on it w/ any pliers.


Ok. I'll report back once I have looked at the new pins and my car...


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## Terry Kennedy (Sep 21, 2002)

Terry Kennedy said:


> Ok. I'll report back once I have looked at the new pins and my car...


Ok, I've installed the driver's side lumbar kit and I'm about to do the passenger's side. I'll take pictures of the passenger's side - I wanted to do the driver's side without the distraction of needing to take pictures.

This DIY is going to be a _real_ pain to do if anyone else attempts it. It doesn't require any special skills, but requires a lot of patience and the ability to see what the people who created the TIS procedures were thinking (as opposed to what they wrote down in the procedures). And many of the spaces you'll be working in are very tight and you won't necessarily know it won't fit back together until you try it.

Also, the 09/2003 (and possibly quite a few others) ETK has the wrong part number for the wiring harnesses - the 401/402 parts come with a power connector with Faston tabs, which I've never seen used on a BMW. I wound up making my own adapter leads since I didn't want to cut into the factory harness. All this will be in the DIY.


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## Kaz (Dec 21, 2001)

Woohoo! Another project from the Terry Kennedy Labs!

Are you doing this with the seats in or out of the car? I dunno about power ones but my manual ones come out rather easily and aren't very heavy to maneuver around the garage to do work on.


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## Terry Kennedy (Sep 21, 2002)

Kaz said:


> Woohoo! Another project from the Terry Kennedy Labs!


  


> Are you doing this with the seats in or out of the car? I dunno about power ones but my manual ones come out rather easily and aren't very heavy to maneuver around the garage to do work on.


I did it with the seats in place. I have heated power sports seats, and I actually dismounted the driver's side to look for a mating connector to the one on the lumbar harness (the 09/2003 ETK has the wrong part numbers for the harness  ). But I bolted it back down once I decided there wasn't a matching connector.

The DIY can be found here. I'll probably be refining it over the next week or so, but it should be enough to explain the job to anyone else who wants to try it already. Please reply here or email me with any questions.


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