Huntsville Racing

Tech Discussion - Lumbar repair for a 2007 Tahoe front seat

TT540 - Thu Dec 22, 2011 9:17 am
Post subject: Lumbar repair for a 2007 Tahoe front seat
The lumber in my 07 Tahoe LTZ quit working a few weeks ago. It will not push forward. It will make an attempt to go up and down, but only with excessive noise/clicking.

Chances are slim I will get some good help here, but thought I'd try. Else, I am off to search the WWW. Which is hard to do given the firewalls at work. Anything with "car" or "forum" or "tahoe" seems to be blocked...

But we now have faceboook.. Rolling Eyes
TT540 - Thu Dec 22, 2011 9:32 am
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My internet searching skillz are mad yo...

Found good enough guidance that I thought I would post it here. GM re-uses a lot of stuff across it's line of vehicles....


Part 1

My lumbar support recently gave up the ghost. I found the lumbar support system GM uses is made by a manufacturer in Canada. Schukra Systems.

The problem with the lumbar is the right drive motor that actually pushes or compresses a piece of metal to give you the bulge in your back has three 14 tooth gears that break under a heavy load or in my case normal everyday wear and tear. Plastic gears of course. If you have you DIC set to memory seat then the seat will always adjust to your position when you enter the vehicle and the easy exit feature also will cause the seat to move all the time. Including the lumbar drive system.

There is another left motor that actually moves the lumbar up and down.

The real problem is you can not find any component parts to repair this item.
The manufacturer, Schukra Systems, I called several times to get answers for parts and they pretty much blew me off or express their concern with no resolve or that this is the sales department issue or I am sorry I really can not help you because you are an end user. WTF.

I spent two weeks messing with them and another two weeks looking for gears that match the ones that broke. No luck, well there is possibilities if you want to pay a machine shop to custom manufacture three 14mm size gears for the price more than buying another system.

Internet price for the lumbar system 180.00. Dealer 244.00.

They use the same lumbar support for the Cadillacs.

So, if your lumbar goes out and you hear a bunch of crackling noise from you seat then the gears have wiped out. The front bucket seat rear cover of the seat comes off and out very easily. Once you take that cover off, the you can see your lumbar system in plain sight. It has two tabs at the top and compression tabs on the sides and lower bottom. Start at the bottom.

Part 2

Well, I broke down and bought the lumbar assembly for my Drivers side seat. It came in last week and when I received it looked like it had been in a warehouse for awhile.

The part number I had from the collision book was not a good number and the dealer gave me another number. I ordered it on line and it is the LH drivers lumbar for a cadillac.

Unfortunately, the assemblies did not look the same and by looking at how it is installed, you would have to take apart the back rest.

On the Tahoe, looking at the assembly from behind the seat, the motor on the left moves the lumbar up and down and the right motor compresses the spring steel to give you the bulge.

The new assembly had the left motor, but the compression motor was on the top right.

Without having to go through the BS of taking everything apart, I took the motors apart and swapped out gears. Would you believe the new motors have metal gears.

Anyways, I kept the other motor and I will now have a set of spare metal gears and motor assembly if it goes out later on the passenger side. had sent me the assembly with shipping for 168.00.
Expensive ass gears.

A word of advice to everyone with lumbar support, when you press the 4-way switch for the lumbar movement and it can not go any further whether you wanting to make adjustments up or down or compression or decompression, once it stops, then hit the switch in the opposite direction for just for a moment.

I say this is because the reason why it can not go any further is the built in plastic stop prevents it from going any further and it is all located in one housing. While I installed the new gears and tested it, I could see the housing bulge when it could not go any further and when pressing the switch the opposite direction relieved the stress on the unit. This might help lengthen the life of the motor gears.

Pr4mnceMan - Thu Dec 22, 2011 10:30 am
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I don't use supports, it's not comfortable and I'm scared I'm gonna get stripper back syndrome when I walk. Laughing
TT540 - Thu Dec 22, 2011 10:36 am
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I am going for my second MRI today for my lower back. My junk's all screwed up. I sometimes have to stick a coke bottle behind my back for reliefe while driving.
Pr4mnceMan - Thu Dec 22, 2011 10:38 am
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Ouch, I didn't know you had back issues. The supports make my back ache if I use them, guess everyone is different.
TT540 - Thu Dec 22, 2011 12:30 pm
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If I work on my chevelle, I have to take 2 Aleve prior or I will not sleep that night. Or, I take one loratab after and sleep like a baby. Laughing I cannot wrench on my car for more than 2 hours at any given time without having to lay down and let my back rest and stop the muscle spasms. Shit sucks.
D C - Thu Dec 22, 2011 2:11 pm
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That's me as well. I have spina bifida and a couple of my lumbar discs will bulge into my spinal cord. The lumbar support+heated seats in my truck is a godsend.
OMGWTFBODY - Thu Dec 22, 2011 2:12 pm
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TT540 - Mon Dec 26, 2011 4:52 pm
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This task is proving to be much harder than the first linked to post suggested. My Tahoe's Lumbar basically ate itself. It is a weird contraption of a device. Midevil even. Gears, motors, cables, springs, levers, rods. All kinds of crap.

Basically, the motor that causes the lumber to go foward does so by collapsing metal piece in to a "V". With the point going in to the seat. The sensing piece that knows when the maximum point is reached is made of plastic. That plastic housing buldged making the sensor not sense. So themotor just kept on winding. Junk was all messed up. Had to remove the passender side seat backing just to figure out how it went back together.

I could not fix it.
Right now, I am unsure how to even REPLACE it given I find thepart number for the assembly. The way it is put together I would have to remove the top half of the seat. yeah, crazy talk. It could have been easy for GM to have made this servicable from the rear of the seat. If that was the case, I could have swapped passenger for driver.

I got my Jury Rig on and now have a fixed lumber support by way of about 8 zip ties. Cool It's even adjustable, just not while driving. Laughing
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