Upgrade: Adding Front Seat Lumbar Support

[Kalevera]

All US spec E32, and all 1995 540 (and maybe 530, I don't know) cars with comfort seats came with driver's side electrically adjustable lumbar support.

Unlike some other manufacturers, this is a mechanical support, not an inflatable air bag, that moves fore or aft at your whim and fancy.

If you have a bad back, or just like a little more support in the back cushion, this is a quick and simple upgrade, and you will be amazed by how much more comfortable the seat is during long drives.

You can install these in ANY US spec comfort seat, driver's and front passenger's. The harness connectors are part of the seat's wiring. So the install involves plugging in the switch, getting the lumbar mechanism in place, and then plugging it in to the seat's harness.

I am relatively certain that they can be installed in electric sport seats as well, but haven't attempted this yet.

I've got these in both of Fritz's front seats:



To do this job, you need the mechanism and a switch. Here's a picture of the mechanism, out of the car:

http://img.photobucket.com/albums/v7...tx/lumbar1.jpg

As you can see, the switch lives on the inboard side of the seat. No need to remove the seat to install the switch. You can stick a hand between the cover and the cushion to remove the plastic blind plug (pops up and out). If the car didn't come with seat heating, you'll find two harness connectors down there, but only one will accept the lumbar switch. Also, sometimes the harness connector is tucked back and down on the bottom of the seat cushion, and has to be fished up (have a look from below). It's a standard blue connector.



Once the switch is plugged into the connector, press it back into the seat's side cover. Remove the seat's back cover (with the pocket) to access the rear and install the lumbar mechanism.



It takes a bit of manhandling to get this in place. You'll probably want to unbolt the arm rest bracket for clearance (2 x 13mm, and an extension) when installing on the RH seat. The lumbar unit is secured by ONE torx screw (think it's a T20, could be bigger), and has a tab that fits into the seat frame. The seat frames are the same whether you're installing on the driver or passenger side, so the screw always goes in on the left, tab on the right. You'll find it easier to seat the tab first, then line up the screw side. This is the hardest part of the job, but also the most essential -- if the screw isn't secure, the mechanism will push itself out of the back of the seat.

Plug in the lumbar mechanism -- it's a black harness connector. If the car doesn't have seat heating, the white one above it in the pic will be flapping around in there as well.

Here's a picture of the frame and torx screw:



After it's in, test it out and enjoy!

A note on used switches: I've removed a few of these, and the majority of the switches that I pull from salvaged cars are bad. Usually it's not just the back lighting, the entire switch doesn't work because it's been goobered up and has sufficiently corroded. These switches are relatively inexpensive from the dealer. List price is $45, can be had for much less than that if you have a good relationship with your parts guy.


If you want to do this upgrade and are looking for the parts, I have one of the mechanisms (someone has dibs on it at the moment) and can probably get another. Switches are another case, but if enough people want them, I can work out a group buy on new ones.


best, whit

[John B.]

How much is the lumbar unit??

[bbig119]

I'm interested.

[stilljester]

I'd like more details - How much $$$

[Dave M]

Interesting. Nice job Whit.

I thought all e34s had the lumbar as my old 10/90 build date 525 has it (Canadian). Thanks for the photos as the drivers side has quit working and now I can check wiring etc. According to your experience, however, it may very well be the switch.

Dave M

[Russell]

comfort seat?? Is the standard seat? Mine are electric with heated option. I am also interested in installing lumbar support. Cost of parts is of concern. Very few used e34 parts in scrap yards. TIA

[Qube]

I have it but it's not enough for longer trips (read; Chicago meet!) I keep a small pillow the in back seat for... erm... this reason. THere are many nice and cheap gel ones out there that won't look out of place.

[Kalevera]

Ah, sorry guys, I published the writeup because I've never seen one on the subject before and it's a good upgrade -- I don't have a stack of these things available. Evan has dibs on the one from my parts car (http://www.bimmer.info/forum/showthread.php?t=28780), and I am certain that he'll want the pictures to install it. I may be able to dig up another one -- PM me if you want me to look into it for you.

I don't know about canadian spec cars, just US ones. And I've never seen these in the passenger seat from the factory.

Dave, best bet for testing it is to disconnect the black connector in the seat back and put 12v on it, see if it moves.

[Alexlind123]

Very nice write up. Where can one find these mechanisms, though?

[brosher]

Thanks for the write up!