Drivers side lumbar support not working

I have a 99 LS with cloth manual seats. Upon entering my vehicle recently the lumbar, which was slightly protruded, went clunk and recessed to the lowest position. Now the knob just spins and the lumbar doesn't move. Any idea what broke and how can I fix it. Anybody have a drawing of the seat and components?

Thanks!

hey the exact same thing has happened to my 99'. It went POP and now that wheel just spins....i haven't gotten around to fix it yet, i really don't know what it is gonna look like in there....As great as these Chevys are and i will never buy anything else but, they sure can be a pain in the ass sometimes...

I got around to fixing my seat about 2 weeks ago. Hear is what I found:

The lumbar wheel is threaded to a nut. The nut is connected to a cable assembly. The cable assembly is routed under the seat, past the seat hinge (closest to the center consol) and up the back of the seatback and connected to a formed piece of rod. The rod is connected to the TOP of a plastic piece that looks like a ladder.

When the wheel turns, the cable assembly and rod pull on the ladder and causes it to bow which feels like something pushing on your back.

Here is what to do:
1. Get a flashlight.
2. Slide the seat as far forward as possible.
3. Flip the seatback forward.
4. Look under the seat for a black cable protruding from the lumbar wheel location.
5. Grab it and pull it.
5a. If it feels free at the wheel end, then remove the three screws that hold the wheel and snap the wheel out to see what broke.
5.b. If it feels free at the seatback end, then you have to dig into the seatback.

I ended up taking the whole thing apart since I had no clue what I was doing. 5.b was my problem.

To get into the seatback here is what I did:
5.b.1 With the seatback flipped forward locate the seam of the fabric (its in the crack between the seat bottom and the seatback). It is an overlapping plastic joint. You will have to squeeze it together to get it apart.
5.b.2 Pull the fabric back and with the flashlight look up the seatback. (I suppose one could peel the fabric up the seat to make it easier, but not me I always do things the hard way!)
5.b.3 The rod probably pulled through the top of the plastic ladder (I’m being kind, the f#%ken* thing broke).
5.b.4 I located another hole on the top of the ladder and attached the rod there. This is where I created a few new words and in hindsight wished I would have peeled the fabric up the seat to see what I was doing, but remember I do things the hard way.
5.b.5 While pulling on the end of the cable, turn the wheel till the cable is as far out as possible. This makes attaching to the ladder easier.
5.b.6 Attach the cable to the end of the rod that looks like an eyelet.
5.b.7 Stick your arms up the seat back and grab the top of the ladder and pull it down, then attach the hook-end of the rod to the ladder. I did this blind and it took about three times to get it in the correct spot.
5.b.8 Turn the wheel to make sure it works
5.b.9 Reconnect the fabric seam.

My last thoughts, I’ll have to do this again because the ladder looks weak at that location where the rod is attached. Sorry so long. I hold no liability for any damage.

Thanks David for the information. My lumbar support went out in my 1999 Silverado a year or so ago. I finally decided to look at it and searched the internet for any info before starting. Due to the excellent info that you gave, I fixed my lumbar within 20 minutes.
FYI
1) Overlapping plastic joint. Squeezing together didn't work for me but you can stick a small standard screwdriver at the end of the plastic clip and separate the two plastic pieces and then just pull them apart down the seam. Very easy.

2) Fabric of seat. I was able to pull up on the fabric only 3-4 inches on the window side and 1-2 inches on the right hand side. The right hand side has the arm rest and I decided not to spend any time figuring out how to get it off. This still allowed me enough room to reach underneath and attach the end of the cable with the hook to the top of the ladder. The plastic top of the ladder has two holes in the center and both looked okay so I just ran the hook thru one of them.

3) I let the cable out to the furthest point, hooked one of the holes and kept tension on the cable till I was able to get the plastic part of cable to the eyelet. I didn't have to pull down on the ladder much.

Thanks again!

Hey guys...

The lumbar support was originally made of plastic... The replacement part is metal... Imagine that...

The part comes as a whole assembly, cable, support, and rods. Takes about 5 minutes to pull the old one out and put the new one on...

Andy