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Then - 1997 S420, followed by 2004 E500 4Matic, and now a 2000 740iL.
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Discussion Starter #1
Recently my lumbar support was inflating then deflating, I believe, per the PSE inflate/deflate cycle that occurs when inflation isn't holding. Coincidentally, I had recently had the transmission fluid/filter changed. After that, I was noticing that the tranny wasn't quite shifting as it was before. Having been disappointed in the shop that did the original work, I took it someplace else for an inspection.

I had assumed that probably (1) the first shop didn't fill the tranny fluid at operating temperature and/or just guesstimated as to full, and (2) the lumbar support dial was malfunctioning (this is because the trunk handle and rear headrests were functioning correctly).

Turns out, I'm told by the shop, that the transmission valve body had a leak/was drawing in fluid then leaking it out on to a computer and two oxygen censors. And that because of the fluid getting on this computer, the lumbar support/PSE functionality was some how being affected. Sounded odd to me, but I figured if indeed the valve body was leaking, it'd be worth the fix regardless of the lumbar connection. And, once I thought about, I did recall that the door lock/unlock switch inside the car worked sporadically, so maybe a computer was affected.

Well, they replaced the valve body, two oxygen sensors and cleaned the computer and now everything is working properly and the transmission is shifting as it had before. They also confirmed that the transmission fluid was a bit overfill.

Just thought I'd mention this as I've never read anywhere on here anybody discussing a connection between the transmission valve body and the lumbar support/PSE pump.

On a side note, recently discovered that you can blow hot air out the bottom vents (and thus to the back passengers) while blowing cold air out the front passenger dash vents by having heat on via the CC unit but also pressing the cold air button on the front vents. I presume it's similar to do the opposite by opening up the back passenger vent (as it only blows cold) while pressing the hot air button on the front vents. I came upon this discovery because I also had the shop fix the passenger seat vent so that it would actually close.

It's nice when everything works. But for sure, not particularly cheap.

FYI: 1997 s420, 73,000 miles. Dealer serviced until about 67,000 miles (when I bought it). Funny, the guy that runs the shop asked "who's been taking care of this car? They've not been doing a good job."
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