Pneumatic Seat Bolsters
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Joined: Apr 2012
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From: So California
1999 C43
Pneumatic Seat Bolsters
Air bags in front seats are not inflating. I used to always hear the pump in trunk run when I got in car, now I never hear pump running or when I changed the settings on the seats pump would run. Door locks all work just fine, I thought door locks ran off of same pump. Anyone have experience with this problem. I know the bags can leak from split seams or broken air lines but my bags do not inflate at all.
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what's the best solution to make tubes not coming off the connections?
using super glue?
zip ties?
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From: Bolingbrook Illinois
1999 C43 Amg
Very easy to put back. I used super glue but the hose still came loose. So added an inch or so rubber hose so there be room to stretch. Problem solved for me.
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sounds like a good idea to use a slightly longer rubber hose as an adapter extension.
factory hoses do they come off from vibrations when car is in motion?
bladders for seat and back support works without problems on my car.
when I try to inflate side supports on both seats I hear no pump - don't see air inflating bladders
maybe side supports have their hoses come off their connections?
my side supports are feeling pumped when I squeeze them however side supports should maybe be even stiffer than a boner if inflated to max?
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12' W204 C63 AMG coupe "T-Rex", 12' W451 Smart Fortwo Pulse (99' W202 C43 AMG + Ultima Can-Am sold)
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From: Bolingbrook Illinois
1999 C43 Amg
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From: Washington, D.C.
2016 GLC300 & 1991 500SL
The bigger and more complicated issue is if the bladders have leaks in them. Given our cars are nearly 20 years old, that's probably the case with yours, in addition to potentially loose fittings on the seat back. All of my bladders developed tears, and my car hasn't seen a lot of abuse. I replaced them all. I encourage you to do them all at once, because some you can replace without taking the seat cover off, and others you need to take it off, or nearly take it off. In any event, it's not a fun process, and should only be done once. Luckily the bladders aren't too expensive from MB.
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Thread Starter
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Joined: Apr 2012
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From: So California
1999 C43
I accessed the PSE vacuum pump in the trunk, pump runs when ignition is turned on for about 1 minuite.
Door locks operate but seats do not inflate, air lines in back of seats look fine. Could there be a switch in the pump that is not allowing vacuum to the lines going to the seats. Some of you certainly have had this same problem.
Door locks operate but seats do not inflate, air lines in back of seats look fine. Could there be a switch in the pump that is not allowing vacuum to the lines going to the seats. Some of you certainly have had this same problem.
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Joined: Nov 2001
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From: Henrico, Virginia
2014 ML350 4Matic
Try plugging the supply lines at the connection block under the front of the bottom cushion (attached to the seat frame) to see if the pump reacts normally, i.e. runs for a few seconds then shuts off. IIRC, the pump will time out if it runs too long. If the test returns the pump to normal operation you likely have leaking bladders.
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05 c55 silver, 98 Imperial Red C43
My car does the same.
The vacuum lines run to the seat controls too (air controls) so check those. It could be loose or unplugged there.
Also I have a spare pump if you need one, I can sell it.
The vacuum lines run to the seat controls too (air controls) so check those. It could be loose or unplugged there.
Also I have a spare pump if you need one, I can sell it.
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From: Henrico, Virginia
2014 ML350 4Matic
Small correction - the seat system uses pressure from the PSE pump. The PSE pump supplies pressure and vacuum, and in the case of the door locks both are used, depending on whether locking or unlocking. The seat system uses only pressure.
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98 C43, 15 Alfa 4C LE, 18 Tesla Model 3 DM Perf, 08 Duc S1000, 02 Duc 998, 98 Duc 748, 01 Miata
I have the same issue but haven't spent any time diagnosing it. I turned all of my bladder switches to the minimum setting and have left it alone until I have time to dig into it.
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Joined: Apr 2012
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From: So California
1999 C43
Thanks for correcting me, The seat bladders do use air pressure. What I don’t understand is if a bladder is split or a line broken I would think the pump would run
trying to inflate and then time out. I don’t see any indication that my seats are inflating. I would assume a lot of us have this problem, sure would like to solve
this problem.
trying to inflate and then time out. I don’t see any indication that my seats are inflating. I would assume a lot of us have this problem, sure would like to solve
this problem.
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From: Henrico, Virginia
2014 ML350 4Matic
Our experience is that the pump is reliable and that the bladders are very likely to be leaking at this age. However, if you are suspecting the pump you can either try my earlier suggestion to disconnect the lines under the seat bottoms to see if there is any air pressure being delivered, or, pull the carpet off the right side of the trunk to access the pump and test it there. IIRC, the air line for the seat bladder system is gray.
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From: Australia
W202 C43 1999
What are the part numbers for the bladders in the seats? These commonly split, especially the bolsters.
The pump will eventually get to a point that it wont run at all, and you will know this has occurred if disconnect the battery for a few minutes then after reconnect it all works again.
I believe there is a diagnostic code that it will set if the pump runs too long and times out.
The pump will eventually get to a point that it wont run at all, and you will know this has occurred if disconnect the battery for a few minutes then after reconnect it all works again.
I believe there is a diagnostic code that it will set if the pump runs too long and times out.
