chmercer

Hi all, having difficulty tracking down what is causing my dynamic seats to not function properly. This is in an 06 e55.

When I got the car they were not working at all. I disassembled the pump and found a melted hose Barb, repaired this with plastic weld, and then they worked for about a week. Both sides dynamic and pulse. Then dynamic stopped, pulse would only blink again. I figured the pump gave out. Fuse was burnt, and replaced the pump.

Now it is working again a little bit. Seats inflate but dynamic does not function and pulse still blinks. Occasionally I can feel the lumbar lose pressure and then re inflate.

I know the pump is good; I can hear no hissing from the pump lines. I left the car overnight and then popped the bladder line off, lot of air came out so I assume that connection is good. I pulled the driver side seat back and again no hissing/obvious failed hoses. When I have the seat back off and accessory power on, I can hear the valve body thing clicking every 30 seconds or so.

Anyone have any suggestions? I am hoping that I don't have to disassemble the seats to check for a popped bladder? Can someone explain where the hose is that feeds the air from the pump into the front seats is; maybe this is the next logical failure point to check?

Any help is appreciated, sorry if this is a duplicate thread, I'm at my wits end over here!

Bean93x

I have the same issue as well. I would like to know where to start..

chmercer

Is it possible that the check valve is leaking causing the pump to run excessively? Is it safe to plug this temporarily to test the system?

chmercer

Ugh I can't hear the slightest leak from anywhere. I can get the vacuum fittings to leak if I torque them so I am almost positive nothing is leaking from the pump side. Ive pulled the pump fuse in case that somehow will reset the system? Next idea is to leave all the seats fully inflated overnight and see if any specific bolsters are less than full tomorrow.

C32owner

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chmercer

Here is what i'm trying today.

I turned the car all the way on, engine running, then inflated driver and passenger side seats to maximum on all bolsters. Then, with car still running, I pulled the pump fuse, and unplugged both seat modules in the seat backs. I wasn't sure if they deflate when the car is turned off to extend life, I figure this way should keep them filled up maximum all the time.

I'll see if anything deflates over the next couple days, I believe this should help pinpoint if one of the internal balloons is leaking?

Bean93x

It's odd, I'll hear a leak from mine that sounds like air whistling for a couple of seconds sometimes up to a minute.. I need to take my seats apart and see what the issue is.. It's just odd because the other day I pressed the pulse button and it didn't blink and worked normally for a couple of minutes and then turned the car on and tried it again only to have the light blink.

chmercer

Had a thought on the way to work - are these pumps somehow coded to individual cars? I noticed zero pressure loss on my drive, I feel like if there was a leak in the bag it would've at least had slight pressure loss from my body weight.

My replacement pump was from an s class and I didn't think anything of it because the plugs were the same and it clearly works.. I may try splicing in the circuit board from my original pump onto this new motor tonight

chmercer

Got it! Sure enough the s class pump circuit doesn't work on e55 for whatever reason. Swapped the mechanical pump and the non melted vacuum hose plate over to the original breadboard and now its back in business. Hopefully this helps someone else attempting repairs with eBay parts in the future!

To condense, you can use the mechanical pump from an 00-06 s class to repair your burnt e55 pump, but you must retain your original electronics.

Bean93x

Where is the pump located? In the trunk on the driver side near the DVD player for the navigation?

chmercer

It on the left side by the DVD player. It is inside of a foam block, in a removable plastic bracket. There are 2 vacuum lines connected to it which pop off with a small flathead. one of these goes to the bladder, and the other goes to the seats i believe. There is a 3rd line connected to the bladder that doesnt go to anywhere, just hangs loose, has a check valve on the end.

Bean93x

Did you have to unfasten the trunk liner to access it or were you able to access it through the DVD panel?

chmercer

I had to remove 3 plastic rivets from the trunk trim, and the t20 torx luggage net hook. I was able to pull the trunk carpet trim piece back enough in this way to fully remove the pump. Inconvenient but i am lazy lol

Bean93x

If it works, it works lol. One more thing, do you happen to have a part number for the pump/unit itself? I want to go out and test mine tomorrow and possibly get a new one to see if it will fix my issue.

Bean93x

Just popped my dvd cover off and I can see two lines going into the pump, I unlock my doors and hear the pump come on but it sounds like it is hissing air. Is that normal?

EDIT; The hissing noise is coming from the pump itself for reference.

chmercer

In that case, I would pop the lines off the pump and pull it out. There are 3 t20 torx to remove, then you can pop open the casing with a flathead. I bet you the plastic hose Barb plate thingy is visibly melted!

Bean93x

I'll have to pull my liner tomorrow and see what's going on.

Bean93x

So, I took my liner apart to get a better look at the pump and pulled some of the foam off to get a good look. I can't see any visual evidence of a melted casing or melted fittings/ lines but I can hear what sounds like a big leak.. I just can't feel where the leak is.. Should I pull my pump and open it up to see whats going on or just find a new pump?

Video I took of what I hear..

Television

All PSE pumps have self protection. If there is a leak in the system, the pump will run for 17 seconds and cut on the timer, in normal use there is a pressure switch that cuts a non leaking system withing 4 seconds.

All PSE pumps are easy to take apart, you could have a hose off or split.

Bean93x

So, I guess my best course of action would be to remove the pump and disassemble it to see what's going on inside?