Soft closing of truck stopped working




https://mbworld.org/forums/sl-class-r230/355467-have-trunk-soft-close-trunk-assist-problems-here-how-fix-diy.html
edit: the car is parked mostly in heated garage, so outside atmosphere doesn’t use forces on car. And the locking mechanism is working completely. The hatch is locking just fine, so I think that the problem is not there. Any suggestions?
p. S. The car has only 51 000 Km on, so it’s not the age too…
Last edited by Klimfilt; Dec 11, 2021 at 03:29 PM.












If there is no difference between Sedan and T-model, so i will try to fix it.
Trending Topics




The Best of Mercedes & AMG




For now I’m not 100% sure where is the problem. I will post updates.
Last edited by Klimfilt; Dec 13, 2021 at 12:30 PM.




It could be the stationary latch assembly or its controller module.
Take a closer look for a chance the latch got in a closed position while the lid was opened... it may be jammed shut.
👀
Last edited by CaliBenzDriver; Dec 14, 2021 at 08:42 PM.




It could be the stationary latch assembly or its controller module.
Take a closer look for a chance the latch got in a closed position while the lid was opened... it may be jammed shut.
👀
I've checked the latch on trunk, but it's not stuck. But i will apply a lubricant ( any idea what kind of lubricant should i use on latches ?), just in case.
I suppose it may be the controller module (small black box in trunk, where the spare tire must be). The pic is not on my car, but this weekend i will check it on my car. May be it's the cord. By stationary latch, you mean the latch on rear bumper (on the picture) or the latch which is on trunk ?




The B latch controller pulls on the release cable. It also needs lube. This is child-play built for easy service.
trunk latch
Lube is a nice gesture but you may need to figure out exactly why the latch system has stopped interacting with your lid.
I lubed mine before it had a chance to quit.
While you have your dirty hands on... also lube the trunk lid pull-down mechanism. In the end it will be way smoother and quieter too.
Last edited by CaliBenzDriver; Feb 12, 2022 at 12:18 PM.




The B latch controller pulls on the release cable. It also needs lube. This is child-play built for easy service.
trunk latch
Lube is a nice gesture but you may need to figure out exactly why the latch system has stopped interacting with your lid.
I lubed mine before it had a chance to quit.
While you have your dirty hands, also on lube the trunk lid pull-down mechanism. It the end it will be way smoother and quieter too.
.By pull-down mechanism, you mean the drive unit which is located on left side in the trunk, right? Like this on attached pic.?




I sort of recall seeing how the lid travel is closely measured... it could be the [Lid + Latch] get synchronized by a learning procedure - Hopefully you'll tell us a bit more after using Star.
Last edited by CaliBenzDriver; Dec 15, 2021 at 11:49 AM.




I will try to make a video of what's happen when the latch is pulling the lid from inside and with removed plastic covers.
If it has something with sync or new learning procedure . i will make a reset with Star on the module and will try it again.
Of course i will write back after i get results with new data




As you can see this mechanism is very often used in other models (W204,W212,S212,X253, W166 and others). So it's very easy to find it second hand and it's not expensive at all (~70-80$) and 20 min of your time to change it. If this 70-80$ are too much for you, you can change only the rotor (the rotor is used in: Mercedes, BMW, Audi, Opel, Lexus, VW, Mitsubishi, Ford, Range Rover, Kia, Hyundai, Mazda, Subaru and other car brands...) inside for 2-25$ from Aliexpress. If you are not sure that the rotor is dead, you can wire directly the rotor with battery with 12v to check it, just for case. Here is a picture whats inside of it:
Three simple plastic wheels + one rotor (and a lot of grease
).The interesting part is what caused the burn of the rotor. When i started to disassemble the mechanism, i barely pulled up (just a few mm) the biggest (first) white wheel up to disconnect it, and suddenly the whole mechanism + cord + the lock on bumper, clicked very noisy and almost to pinch my other hand which was on the locker on bumper. So i can conclude that there was a stuck on the locker on the bumer:
And this jam caused the burning of the rotor, which is very very simple rotor. May be if i can find it in my daughter's toys

So my advise is to maintain clear and greased the locker on the bumper and regularly to check it for dust to avoid this issue.
Last edited by Klimfilt; Dec 20, 2021 at 10:43 AM.
As you can see this mechanism is very often used in other models (W204,W212,S212,X253, W166 and others). So it's very easy to find it second hand and it's not expensive at all (~70-80$) and 20 min of your time to change it. If this 70-80$ are too much for you, you can change only the rotor (the rotor is used in: Mercedes, BMW, Audi, Opel, Lexus, VW, Mitsubishi, Ford, Range Rover, Kia, Hyundai, Mazda, Subaru and other car brands...) inside for 2-25$ from Aliexpress. If you are not sure that the rotor is dead, you can wire directly the rotor with battery with 12v to check it, just for case. Here is a picture whats inside of it:
Three simple plastic wheels + one rotor (and a lot of grease
).The interesting part is what caused the burn of the rotor. When i started to disassemble the mechanism, i barely pulled up (just a few mm) the biggest (first) white wheel up to disconnect it, and suddenly the whole mechanism + cord + the lock on bumper, clicked very noisy and almost to pinch my other hand which was on the locker on bumper. So i can conclude that there was a stuck on the locker on the bumer:
And this jam caused the burning of the rotor, which is very very simple rotor. May be if i can find it in my daughter's toys

So my advise is to maintain clear and greased the locker on the bumper and regularly to check it for dust to avoid this issue.
I got the same prblm and by the end I found almost the some rotor in a toy ! I exchanged and it worked !



