RuckIt

Realized I had this in the wrong forum.

I pneumatic seat pump is cycling about every 30 seconds for a few seconds at a time, then it heats up too much and turns off until the car sits for a bit and it can cool down. This happens even if all my seats are set for zero calls. Does this mean the pump and or the reservoir is leaking? Or is air being fed to the seats all the time and then the valves just control what is being inflated or not? Trying to pin point where I should be looking for a leak as I can't hear anything obvious. Bought a stethoscope to hopefully help me out. 2007.

thanks!

BOTUS

seat bolsters and lumbar are pneumatic, they get air as the car is unlocked - the pipes to feed or a bag has broken (normal), would be best to pull the fuse if you can't be bothered to cure the leak

RuckIt

RuckIt

That’s an annoying bug in the forum, if you type a reply and then add a photo, bye bye reply. Nice 2002 programming.

anyway, the seat bolsters all seem fine as they inflate and deflate and hold air. So likely the pump or the reservoir. Trying to track down what all the different color tubes do but can’t find anything online.

BOTUS

its usually broken pipes inside the seats - they fracture and leak

https://mbworld.org/forums/s-class-w...fixed-b-3.html

Arrie

I just went thru this issue. I had exactly the same problem with my 2013 model that was totaled. Thus 2012 had the same safety valve leak issue. Valve is on the tank and you cannot buy the valve separately. It comes with the tank. $360 from my dealer. There are liwer cist options but thus way I know it is a good part.

Problem was with the seal between valve and the stud it sits on. Funny thing was the seal was holding if I tilted the lines a bit.

Check yours when it is pressurized by moving the two lines connected ti the valve.

RuckIt

Thank you, I moved the lines all around and couldn't find any source of leaking at the pump. I used a stethoscope all around it and it was dead silent, so I moved on to the front seats as those are easiest to access and I've had to replace a valve in the driver seat before.

I disconnected both supply lines to the seats and plugged them using some drip irrigation tubes with plugs on the end and watched the pressure in Xentry and sure enough it was holding (well, dropping ever so slightly but not like before, would take probably 20 minutes to have the pump kick back on again if it went that low). So I knew it was one of the seats. I plugged the driver seat back in and the pressure stayed, so it is the passenger seat.

I took the back off the passenger seat and disconnected the air line going into the Y valve and reconnected the supply line under the seat. Put a plug in that line behind the seat and the pressure held, so not that line. Then I disconnected the Y adapter that goes to the 1) massage function and 2) seat bladders. Plugged the supply line into 2) seat bladders and pressure held. Then plugged the supply line into the 1) massage bladders and the pressure dropped rapidly. So found the problem area, massage bladders line or valve, or bladder.

Now those being accessed from the front of the seat I have no idea how to tackle that and may just leave it non functioning as no one ever uses that feature anyway.

Well, hope this helps someone in the future narrow down. I should have taken some more photos, but if anyone has any problems in the future trying to figure out where the leaks are I know have about 12 hours figuring it all out.

Thanks for the help.