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Everything that works: both seats fore-and-aft, up-down and tilt, seatback angle adjustments, headrests up-down, memory seat settings, ... all the seat settings work properly except the lumbar support adjustments. I can turn the dials full range in each direction, but nothing happens to the lumbar support in the seat backs and I hear no escaping air.
The PSE and everything it operates works properly ... everything except the lumbar supports.
I read other posts on this forum ... posters suggested pulling and checking several fuses, but that accomplished nothing.
The PSE pump has several managed outputs so even though the pump is working doesn't mean that all circuits are active. You may have a hose off, pinched or damaged. I would look closely around and under the seat and maybe even remove the seat.
May need with aid of a helper to check the MKL connection at the PSE pump in the trunk when turning the dial from 1 to 5 on the seat. If both seats do not function the solenoid in the pump might have failed. Could be line leak at the connection MKL, crack in plastic tubing, poor seal.
Most likely seat bladders have failed. PSE pump will shut off a leaking circuit when leaks occur allowing the other circuits to continue to function. I replaced the bladder on my drivers side recently. The bladder itself is two piece construction and one of the seams had separated on mine. I tried to repair the seam with epoxy but no luck. Finally purchased a new one from Huskers.
Most likely seat bladders have failed. PSE pump will shut off a leaking circuit when leaks occur allowing the other circuits to continue to function. I replaced the bladder on my drivers side recently. The bladder itself is two piece construction and one of the seams had separated on mine. I tried to repair the seam with epoxy but no luck. Finally purchased a new one from Huskers.
Good luck,
Bob
Bob, I just purchased a 2006 SL500 that spent its life in Florida so some of the interior plastic parts are baked, as might be expected. The lumbar function does not work on either seat but there is air in the lines feeding each seat so the PSE pump is feeding the seats once I disconnect/reconnect the consumer battery (I installed a battery disconnect switch since this will be just a summer car). I can hear a hissing sound coming from the rear area of each seat when adjusting the lumbar control to the open position (full open at 5) so the problem is not external to the seat and may be the bladders. I did not take apart the seats to troubleshoot further. In looking at seat component diagrams from M-B on their dealer websites I do not see the bladders, only a frame and seat pads. Is the bladder the same as the back seat pad? Or is it part of the frame? Part number if you know it from your purchase? Thanks in advance - Don
It's either hoses that come from the PSE pump to the seat or bladders themselves.
Hoses are a common issue as they are routed in a way that makes them bend every time the seat moves back and forth. To inspect these you have to remove seats, the hose is underneath. This forum has full set of instructions as to hot to disassemble it. If this is the first time with seats, it's most likely hoses. And hissing comes propably from the punctured hose as it's quite hard to hear leaking bladders - they're inside the seat and under seat cushions etc.
As for bladders - there are two types of these. One for common seats and the other for multicontour seats. If you have a dial with numbers 1 to 5, you have the light version. There are some manuals on how to replace it and many use not the original bladders, but other inflatables, from rubber gloves to IV packs.
In case of multicontour seats you can check it by Star Diagnosis - it can inflate each bladder separately and measure the pressure.
Thank you for your reply. My car has the common seats, not the multicontour seats. Is there a M-B part number for a bladder? There is no "bladder" listing on the M-B dealer websites, just pictorials and part numbers to the seat pads (one bottom and one back) and a seat frame. I suspect that a split bladder is is the problem, since the hissing noise is common to both seats and the hoses underneath flex nicely and visually seem fine. This car suffered from Florida's heat so I am in the process of replacing other plastic parts (LCD's in the cluster, screen on the COMAND unit) so it is probable that the seams on the bladders split.
I have been told that the bladder seams fail. I think I killed mine when I was repairing the front lock cylinder. I have tried to find some but they ar rare and run about 150.00 each. Getting the seats out to repair is a royal PIA.
Thank you. You are likely correct, as the hissing noise is coming from that area. In the interim I plugged the discharge ports on the lumbar control actuator (front of seat knob) with tiny removable nails and electrical tape, so that other devices such as door and trunk lock functions are not adversely impacted, and the pump does not needlessly run. Once we have some nice weather here again I'll pull out the seats and troubleshoot them. Might be heading to Walmart for lumbar support cushion stuffing material if the project repair becomes economically unfeasible; can still use the control and hoses to inflate the grandkids balloons . . .
Last edited by soldbydon; 12-22-2020 at 12:41 PM.
Reason: reduce content
The base lumbar bladders are not all that expensive from Mercedes. The left lists for $135 and the right for $94 (typical Mercedes pricing logic). You should be able to get 20-25% off of list, so lets say roughly $100 left / $75 right. Multicontour is another story.
Post a tutorial when you do repair them. I started to remove my seats but there is a connector that appears to take a special tool to release. I got the seat all ready to come out except for that. BTW the seats are heavy. Make sure you have help.
Question to the group. Can this job be done without removing the seats? The seat back has to be removed to gain access to the bladder but to do that, do the seats have to be out?
No need to remove the seat and no special tool required that I know of. I haven't replaced the lumbar, but I have replaced the cover/padding which is basically the same job.
No need to remove the seat, however the eccess is easier when the seat is out. The connector under the seat does not require any special tools to disconnect. Look closer, there is some kind of lock on it. Pull it and the connector comes off easily
This is good news! I’ll take a look at the WIS again and look to do this over the winter. Lowering the top will make this easier, I believe it should give a bit more room to move around.
With top down you have quite enough place to do the work. It's quite a procedure as you have to carefully remoce switches, headrest and other seat parts without breaking it. Below is some example of what you get in the end. To remove the bladder you need to remove leather cover and to do so you have to disconnect seat belt from the bottom of the seat. I did it to check my side bladders, but with no success - i couldn't find any leaks.
My lumbar setting zero out no matter what # I place it on... any idea why?
My Lumbar settings zero out as well as dynamics settings. Has anyone figured out the solution? I'm hearing more and more R231 SL550 owners are experiencing this issue. Please advise....Thanks in advance!!!
You need to remove the seat back and cover and then determine if the leak is in the bladders or in a line or fitting. It is not that difficult of a job, but it does take some time and is an expensive fix at the dealer because of the labor involved. You should be able to find numerous posts on here on how to remove everything and some alternate ways to fix the bladders if you don't want to buy new. From the way you are describing it zeroing out, I'm assuming that we are talking about something later than the 2004 in your profile, but the basic premise is the same. The multi-contour or dynamic seat control will turn off any air circuit that it determines is leaking and will disable dynamic or massage functions that would use that circuit. Once you fix the problem, you may need to reset the control by pulling a fuse or using a scan tool.
10-11-2016, 08:20 PM
