My 2000 s500 has broken airlines running to rear seats lumbar control and into the cushion. Does anybody know procedure or where to purchase replacement parts to fix all pse air lines associated with lumbar controls. And also I can turn lumbar off and all features work, soft close, door lock/unlocking etc. But when I close trunk it will pop pse fuse again. Do I need to replace trunk soft close actuator as well the air lines seem fine going to it


As far as finding replacement air hoses for the PSE system the dealer would be the most expnsive but easiest soltuion. The other option is to go to to a junk yard and pull the lines that you need. If you have a junk yard with EU cars, they will have a W220 for sure. But if it was my car what I would do is remove one of the hoses, measure Inner Diamter and find any replacment hose online. 

As far as I know there is no seperate fuse for the lumbar. Duble check and let me know if I am wrong. If you don't find a fuse, you can crimp the damaged line at the end so that the rest of the system especially doors continue to work. 

Make sure to check the air line under the seat though. They do break near the connector. 

If your PSE keeps blowing, you may have a bad PSE motor though. 


Unfortunately with this car it is all connected. When i keep the lumbar option turned off at all seats the PSE pump works perfectly fine for the doors soft close feature and the door locks as well as the raise and lower of the headrest. I could easily live without lumbar and keep them off but one I want to sell the car and 2 even if I keep lumbar off as soon as I close the trunk the soft close actuator or something involved in the hitch will pop that fuse again then your stuck without locking and unlocking the car other than the old school way of doing them all by hand. I've narrowed down 2 issue areas being lumbar controls and shutting the trunk. But we do have just 1 EU salvage yard I will go see what I can find

You are correct that they are all connected. That's probabily why they didn't put a separate fuse for the lumbar support.

The most important issue here is to fix the actuator problem. It sounds like the actuactor is stuck creating high vacuum in the PSE motor which in turn draws too much current. Of course you can open the trunk actuator and inspect maybe you can identify and fix the issue.The other option is to replace it with a used one. Buy a use unit online, see W220 Trunk Lock Vacuum Actuator (part number 2208000478). 

As far as lubar support you may have to keep it off until the leak has been identifed. But the new owner may not mind lubar support not working but would want the door lock/unlock to work.

Yea that's exactly what I was thinking. Lumbar rarely gets used anyway in any car. I would just have to tell customer to not turn those dials on. And I will just replace actuator and see if that helps because the lines running to it are in perfect shape. They are known to develope a leak where the actuator connects together at the center. Some have fixed with epoxy but I don't beleive in rigging things...especially when selling to another person. I got a great deal on it. It's a 2000 s500 only 120,000 miles on it. I've replaced the transmission pilot bushing because these cars are well known for those seals to go bad and tranny fluid leaking into the electronic plug that communicates with TCU. The fluid even wicks up the electric wires and goes into the TCU. Lol weird but it happens alot. Mercedes will tell ppl they need a new tranny when a $15 part is the problem. I opened the TCU and cleaned out the tranny fluid from it put it all back together and bam it works perfectly. I did have to replace 3 air struts also but I found a place that sells brand new ones for $150 ea. So all I have left is the PSE thing, a duo valve aux pump to replace so the heater will blow hot air again and replace level sensor and calibrate the ride height then its ready to go. In my area the car is still worth $5000-$6000 and I paid $1500

Interior is flawless, navigation, rear reclining seats, heated seats front and back. The whole 9 yards. I'm secretly wanting to keep it lol but there's plenty more out there. I find mercedes with no warranty that owners sell for cheap because of how expensive they think it will be to fix and I do it myself. 

Thank you for chatting with me about this. Your Insight is very much appreciative 

That's what I would do. Just get a "new" actuator online. Also you can check if any local junkyard has that part. Go to and look up the part and rember to enter your zip code.

I like your approach. You never know how long epoxy fix would last. Don't worry too much about the lumbar support. No one is going to pass on a good car becasue lumbar settings don't work.

The W220 are awsome cars. I bought a cheap one several years ago. Like you I do love working on them, this one keept having issues week afer week. It just wasn't mainted properly. I guess it was my fault for buying it. Now I have just bought W221 as a side project. It had bad air suspention (already fixed) and don't go into gear. Still working on the transmission issue. You can see it and follow the progress here.

Btw, you seem to know a lot about Mercedes-Benz. There are a lot of members here that ask questions about these cars. If you could share your knowledge that would be greatly appreciated. You can easily see all the recent quesions on

Would love to hear how thing go with this car.

Keep us updated.


I would be more than happy to help as much as I can. Im Going to look at your tranny progress and see if I can help u there I've fixed 2 already myself

Regarding your tranny. The 722.9 has the TCU molded into the conductor plate instead of in the engine bay. Have you had the tranny scanned and if so what did it tell you. Mine had a bad speed sensor that's molded in conductor plate as well. Not many shops will touch it and tell u to go to the dealer. I found a solution to fix that for $230. Also these cars have a notorious issue with the connector plug and pilot bushing. When under your car you would have to unplug the connector plugs that attach to the tranny. Once u unplug it the pilot bushing is the area that plug went into when connecting to the tranny. There is a little nut in there u have to unscrew to pull that pilot bushing out. 

The main problem is the o-ring seals on the bushing go bad and tranny fluid leaks into the area the plug goes into and prevents the electric communication from tranny to the engine which makes the car go into limp mode or not moving at all. 

Let me knw what your tranny codes are when it's scanned. And I can help u more.

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