Hello everyone,
I have a quick question about my trusty 2008 S550.
Both front active dynamic seats are no longer working. I mean, the seat positions adjust like normal. but the air chambers no longer work. I cannot adjust lumbar, bolsters, shoulders or massage.
What will happen on the menu is when i try to select an adjustment with the rotary wheel such as inflating the side bolsters, the menu will let me select the more inflated setting but will then revert right back to zero. I dont feel any difference in any of the seat adjustments or maassage.
Could the air bladders in the seats be bad?

What must I do to rectify this? Do I need a new seat or can these features be replaced independently?

Thanks in advance,
E

 

It is likely either a blown bladder, seat control module, or air pump that has gone bad. Any of them can be replaced individually. STAR may be able to pick up a fault code to pinpoint the problem.

If it turns out to be a blown bladder, you can do a search of the board here as there was a forum member who was able to perform his own repair on the bladder without having to replace it.

 

Brilliant response! Thank you. I’ll start digging on this.

 

Good evening everybody.

I have a S550 2008. I have a similar, but mixed issue with the driver side seat.

The Lower and upper Seatback lumber support works. The Seatside works. The Massage feature works. What does not work is the Seatback Side feature. When I adjust the level it drops back to "0". Similarly the Dynamic seat feature drops to "0". I believe that is because the Seatback Side feature is not functioning.

Any suggestions before I take it apart?

 

check back a few... very detailed repair stuff with photos on one recent post (last 6 weeks)

the gist is the electronic module dies and all the air pipes fracture

 

This is the thread with the details on Dynamic seats:
https://mbworld.org/forums/s-class-w...g-fixed-b.html

I still need to update the software for my new modules, which is a trip to the dealer. The dynamic works sometimes, and other times drops to zero as others have seen.
And my shoulder valve solenoids are stuck 'full', won't deflate, so they are currently disabled by detaching the fill hose to the valve. Needs replaced with good valves. This is a work in progress.

 

Mine has done the same thing a couple of times. Then I hook up the laptop and run DAS to troubleshoot, nothing is wrong, and it works fine afterward. I suspect buggy firmware that just needs an occasional reset. So far I’ve been lucky, it’s never been an actual problem with hardware.

 

that's exactly what I thought was wrong with mine...
and it was running last available software …
But after I swapped the module its now working correctly without bugs and glitches... the later part runs the SAME software but later hardware... the module's like the rest of the car is budget rubbish marketed to be premium

 

Happy with my new to me W221. We've had it two weeks. It is a 2007 s550 with about 55k miles. Enjoying learning all of the features on what is now an older car. Unfortunately, because of the pandemic I don't have many excuses to drive it.
This is my first post to the forum, and am hoping this is in the right place. The dynamic seats work, but shoulder bladder on the driver's side is too full when it is set at zero. Settings make it go up and down, but I can't get it to go down enough. Someone on the forum said they had that problem and were able to reprogram it using STAR. My questions are:

- Does it make sense for an owner of 1 Mercedes to purchase this? I read there is an annual subscription. And it seems like there would be a steep learning curve to use it.
- Are there alternatives that would be more practical for a DIY'er?
- How do I check to see if the firmware on the car is current? Does that require a trip to the closest Mercedes dealer?
- Any other way to get the shoulder air bladder to fully release? It pushes my shoulder blades forward.

 

if it inflates and deflates then sound like its working..... I have HUGE issue with these seats. they have always crippled my back. I have to have way more incline on the back rest to stop the horrendous cramps and stress the gives my shoulders...…

I suspect the seats where designed to accommodate the lizard people's tail who get to buy these cars - did you watch V ?

 

Good evening folks.

Update on the repair on the seatback sides working randomly. I took the back off the seat and accessed the wires. In particular there are a bundle of wires attached to a single combined connector. After jiggling the wires around, I discovered one of the wires was not making a connection completely and if I held it in a certain position the seatback sides worked.

I took the easy way out. I snipped off the connector and used a wire nut that tied all the wires together. I added a single additional wire and tapped into the original connector that led to the module. It seems to have worked and I think I resolved my issue.

Sorry I did not take a video of the fix but I followed the directions from a post regarding the bundle of wires.

 

Let’s answer these questions...
Even if you only have one Mercedes, the Star will pay for itself on the first diagnosis and repair, plus it has value when you sell the car.
It does not require an expensive subscription unless you plan to use it for software programming or updates. Use the dealer.

Firmware/software requires the Star, or trip to the dealer.

The uncomfortable shoulder bladder issue, with it remaining full and not releasing is either:
- bad software
- bad wiring
- bad solenoids allowing fill, but not release

I need to replace my solenoids, but chose the quick repair, which works fine for me:
Remove the seat back (2 screws)
Find the shoulder solenoid (see posts https://mbworld.org/forums/s-class-w...ml#post8152190
Disconnect (cut) the line to the shoulder bladders at the solenoid. The shoulder will deflate, and never inflate again!

Replacing the solenoid with a proper functioning one will also fix this problem correctly.

 

Thank you Botus and Kbob999. Letting the air out manually is a great idea. It sounds like my problem is software, since it does inflate and deflate. It just doesn't deflate enough.
That was what I needed to hear about Star. I'm enjoying the car and expect I'll eventually run into reasons to need a diagnostic tool. I'll start with the Marketplace on this forum.

 

I’ve said it before, and I’ll say it again... if you are inclined toward DIY service on your vehicles, a laptop with the diagnostic software and an adapter will pay for itself very, very quickly.