04 E55 AMG: Restore multi-contour seat operation

[kevm14]

Like the TPMS, this was not functional when I bought the car. Of course the seats are very comfortable and supportive as is but I'd like the air system to work. I am told the pump is in the left rear trunk area (when I pull the cover to check for a TPMS module I'll check out the pump, too). Anyway, the pump is supposed to run immediately after engine start I guess and checks for pressure in the various seat bladders. I guess it actually has a memory so it will maintain whatever pressure you had it set at. Well, I do not hear anything at all. So maybe I just have a dead pump. That would be pretty sweet. I'm probably not going to tear my seats apart and replace blown bladders but if a line was split I could patch that. And again maybe it's just a dead pump.

Now I'm confused though. Is this the pump? https://www.ebay.com/itm/223892249579?_ ... %3A2334524

Or is this the pump?
https://www.ebay.com/itm/313206412386?h ... SwDjlfUd0f

Maybe the second one is the pump (single one in the trunk) and each seat gets one of those manifold things....confusing.

[kevm14]

I "solved" the mystery when I was in the left side of the trunk (three birds one stone). So I simply bought a used pump based on the actual P/N of the pump that does NOT run when the car starts (it is supposed to run for 20-30 secs every ignition cycle evidently and mine does not).

Anyway I ordered a used pump on eBay for $38.52. I guess it is also a central locking vacuum pump in addition to a seat pump in some applications. Maybe it's just a vacuum pump? I don't understand how the system works.

My pump

20210507_174850.jpg

Used pump

20210512_150247.jpg

20210512_150256.jpg

But yeah, kind of like with the TPMS I am a little skeptical that I can just throw a pump on here and everything will work. Based on my knowledge so far I may also have a line leak under one or both seats that caused the pump to burn out. We shall see - and if so that isn't too hard to fix. I may be able to fix with some heat shrink tubing even. Can't hurt to try the pump and I really can't diagnose the system if this pump is not working so it was certainly worth the risk.

[kevm14]

But yeah, kind of like with the TPMS I am a little skeptical that I can just throw a pump on here and everything will work. Based on my knowledge so far I may also have a line leak under one or both seats that caused the pump to burn out.

Well I got my new pump and it doesn't work. Actually I heard it run just a little and then it stopped. So I plugged in my old one and sort of beat it against the trunk area and it started running. So I got back into the car and.....yeah the seats work now! The seats appear to have the following adjustments:
- Lumbar. You can inflate and deflate the lumbar.
- I think it has a lumbar height adjustment? I can't quite figure it out but I think that's what it is. I could read the manual...
- Seat back bolster. It seems there is a leak either in the bladder or a line to the bladder because this doesn't seem to inflate properly.
- Seat bottom thigh bolster. This seemed to work but didn't do much. It's not like it extends a few inches or something.

I should try the passenger seat. I hit a few buttons and it seemed to work at least. So I will be returning the eBay pump which seems DOA. But my pump is working for now. Yay?

[kevm14]

Pump stopped working. So I tried another eBay one (got a refund on the firsr one). This one works. Fixed again!

20210518_145234.jpg

[kevm14]

Still works this morning! Fixed forever?

This repair cost me $42.80.

[kevm14]

Still works. Here is the info on what the buttons actually do.

E55 Multicontour seat info.PNG

I guess it's what I thought. The up and down move the position of the lumbar somehow. Everything else I understood already.