blueduramax

On my 2005 SL500 the lumbar supports do not work. I have removed the seats (almost at least) opened the black covering looking for compromised tubes. All looked good. Took out the seat switches, tested and inspected them, all looks good. There was no air pressure coming from the pump in the trunk. I took off the ground wire on the accessory battery hoping it would reset and pump air, but it did not. Everything else is working as it should including the soft close trunk. Cannot see any damaged tubes in trunk. Partially inflated seat bladders with air and they seem to work as they should. Any other ideas or help appreciated.

chad500sl

If you have Xentry/SDS, clear the faults in the seat control modules. I had to do this once on my driver seat to re-enable the system. I was then able to fix the leaky lumbar bladders. This doesn't seem to be needed all the time as my passenger seat leaked without disabling the pump. If your bladders leak, consider using 500ml IV bags as a replacement. Not easy to get, but they directly connect to the existing tubing.

blueduramax

My car has only 69000 miles on it and our climate is mild, so I am guessing the bags are still good. They did inflate when I tested them though there could have been a slow leak. It seems on my previous R230 I found a way to reset the air pump without using a zentry or anything. I thought it was disconnecting the rear battery but maybe it was a certain fuse. Any other ideas welcomed.

chad500sl

If your door locks are working fine, then likely the PSE pimp is working correctly. Is it both seats, or just one? The PSE pump has an actuation valve that controls air supply to the seats. Possibly this could be stuck/not working, but that seams unlikely. Could also be a broken line, but I'd expect that to affect only one seat.

The PSE is easy to remove and clean. I suggest cleaning it and trying again. I had a PSE lockup and start blowing fuses. Even though the trunk was dry, the PSE plastic case was full of water. Cleaning, lubrication, and re-install fixed the issue. It doesn't sound like you have an issue with the PSE, but it's very easy to clean. You can then manually blow some air thought the tubes.

chad500sl

I have two 2005 SLs, both of them had most of the bladders leaking. Based on that experience, I find it difficult to believe none of your leak, being the same year. If so, you're damn lucky!

blueduramax

Both doorlocks work fine, even keyless go works. I tried blowing back thru the air lines from the front seat switch and no air would go thru. I don't think there is a broken line. Thanks for the tip. Todays project is cleaning the air pump!

chad500sl

As motivation, the pulse massage feature is truly spectacular after you've spent a few hours bending over the car fixing the lumbar. It feels nice, but the mental satisfaction is on a whole different level. Good luck!

I suggest checking the manual key on the trunk before disconnection the PSE and/or battery. Don't get locked out by mistake...

blueduramax

Finished taking the air pump in the trunk out. Opened it up and it was pristine (no sign of any moisture). Did not see anything to clean. Re-installed (hoped I got all the pipes hooked up right). No broken or twisted hoses that I could see. Still no air seems to be going to the bladders. In other words not working. Still searching for the answer.

matk

When you opened it up, did you just check inside the plastic casing or did you remove the top once inside and check the impellor?

The Impellor is made of carbon and can shatter leaving the pump not working but everything else looking dry and intact. This happened on mine.

If the impellor has gone it’s about an hour to replace and you can source replacement part from eBay

tsx69

Hopefully this will help you. First I purchased my car from the USA and brought it in to Canada in 2022 2004 SL600 although this fact is irrelevant it will explain my issue and my fix and perhaps help you with you issue. Second my issues were very similar to yours all my PSE items were working and when I purchased the car both the passenger and driver seat worked flawlessly. My issue, the pulse button would light up but I had not power to either my driver seat or passenger seat and as I read many threads on this site and others I realized there were a few of us that seem to of had the same issue. I looked for leaks and spent some good money trying to chase down the problem. A few months after having the issue I realized the issue started after I had my car in for service and had them reprogram my chip for Canada, KM's and Daytime running lights. I went back to the shop (not MB dealership) and asked if this reprogramming could of caused my seats to stop working. Answer was I don't see how it could have and he did a few things and came to the same conclusion that the pulse lights up but no power and of couse said I should book the car in and they will take a closer look. At this point I let it got. As I do lover the car the joy of driving my 500hp car I decided I would order the Renntech performance chip for the 630HP ( it is awesome by the way!). I installed the software and as immediately tried the seats after the update and guess what, BOTH SEATS WORKED IMMEDIATELY after the chip did it's thing.

In short if everything else is working look for a software issue, it certainly appears to be of been my issue. Hope this helps