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The Mercedes tech identified a very slow leak in the drivers’ side Backrest Sides (inflatable bolsters). The leak is in the inflatable bolster itself and not in the air line.
Mercedes uses a pressure/vacuum tester--similar to an aircraft pitot static tester--to pressurize and to pull a vacuum on the inflatable seat components to check for leaks.
The tech explained that the reason the slow leak caused an intermittent failure in all Active Multicontour Seat functions in both seats, is because when a leak is detected, the Seat Pump Motor shuts down to protect itself from overheating. The pump then resets after a period of time.
The inflatable bolsters come as a set, i.e., each seat has two, and cost around $300.00 CDN; I have an appointment on 26 Jun. to have them installed.
I’m still under warranty so will let them do the job; however, according to the tech, it’s not too difficult a job to R&R the inflatable bolsters. If that’s the case, I’m thinking a simple bicycle tire repair patch will do the job if it ever happens again.
Hopefully all goes well and I'll report back to confirm the fix.
Bladder leaks are somewhat common, although more for the massage functions. Not a big deal although much depends on the quality of the tech performing the repair. Not for the actual repair, that is but the removal and re-install of the leather covers.
We had that done on our last SL and the back cover somehow appeared to be put on in a way that the backrest had a bunch of wrinkles where it should be smooth. They tried to straighten it out but failed and eventually installed a brand-new back seat cover.
My recommendation is to take pictures of the seat surfaces and then upon pickup compare that everything looks exactly like it did before…
Bladder leaks are somewhat common, although more for the massage functions. Not a big deal although much depends on the quality of the tech performing the repair. Not for the actual repair, that is but the removal and re-install of the leather covers.
We had that done on our last SL and the back cover somehow appeared to be put on in a way that the backrest had a bunch of wrinkles where it should be smooth. They tried to straighten it out but failed and eventually installed a brand-new back seat cover.
My recommendation is to take pictures of the seat surfaces and then upon pickup compare that everything looks exactly like it did before…
My massage function just started to shut down after 5-10 minutes regardless of which setting was selected. Is this likely a leak like the OP issues?
Quite possible. Try the other functions, one at a time to isolate the bad actor, i.e., inflate the side Bolsters to max, one seat at a time, to verify they hold air. Then set the Lumber to max in each position.
Is the massage fault intermittent?
Do the other Active seat functions still work, or do they all stop working when the massage fails?
A dealer friend of mine, who sold these cars for years and still does, told me there is a time interval in massage mode. That is, it shuts down automatically after some time. I’ve never experienced this, but the most I’ve ever used massage is for about 20 min. at a time.
For those following, I apologize for not getting back sooner. The dealer ordered the wrong part and we had to reschedule for a later date.
Apparently, the whole assembly (P/N 231-800-10-78 see attached pics) is required when replacing the active side bolsters.
I’ve only had it out for a short run, but everything is working now.
There was a slow leak in the seam of the drivers left side bolster. Thinking it could have been caused from getting in and out of the vehicle; however, I usually sit and swing my legs in so not convinced that was the cause.
If anyone experiences a similar problem, I’d recommend first trying a tire repair patch before taking to the dealer. The part was around $600.00 and it took a good 8 hours to replace.
Sounds about right.
I have a 45 minute ride to work part of the week and whenever I start the massage function at the start of my trip it will always turn off before I arrive, so I just start it again. I guess there is something to that time interval statement.
Originally Posted by hornethandler
A dealer friend of mine, who sold these cars for years and still does, told me there is a time interval in massage mode. That is, it shuts down automatically after some time. I’ve never experienced this, but the most I’ve ever used massage is for about 20 min. at a time.
Last edited by ThatsMyDawg; 08-28-2023 at 12:09 PM.
05-18-2023, 04:57 PM
