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I have a 2011 SL550. The trunk lid will open, but not raise on its own. Once manually raised, it will close on its own. Is this part of the same issue as the pinned thread on the soft raise issue?
On my 2003 SL55, I replaced all 5 struts (2 for hood, 2 for the trunk, and one for the trunk opening for raising/lowering the top. The new struts still do not push the trunk lid up when the latch is released.
You bring up a point I do not understand. I put new trunk lid struts (aftermarket) on mine (2003 sl 500) when I bought it and it pops the lid ajar but not fully open. The one's it came with were shot. In a brand new car was the strut powerful enough to fully raise the lid? Do I need a Mercedes brand strut to completely raise the lid? If so is it hard to close due to back pressure?
moretech
On cars with the automatic trunk open/close option, the vario roof hydraulic system is used to fully open and close the trunk. Without that option, the trunk uses simple gas charged Lift-O-Mat struts to hold it open once manually lifted. In the OP's case, it sounds like his car has the automatic opener option but it's not working. I posted on his thread over on Benzworld that it could be the Trunk Lid Position Sensor (B24/16) is misreporting. Here's where it is located:
I've been chasing down a trunk problem with my 2013 SL550. The trunk will not operate correctly when it's cold and the car has been sitting. Pull the lever and it pops the trunk but it doesn't lift open. Pull the lever again and it opens. Push the close button and the trunk closes, latches, unlatches, and re-opens. It will do this over and over again. I found that if I push the emergency release button in the trunk while it's open and then push close it will lower, but then it either doesn't latch or the latch will cycle continuously (latch/unlatch) until I pull the lever again. After a lot of iterations and possibly the car warming up some I can eventually get it to close and latch.
I was fairly certain it was a bad latch mechanism (latch position switch), but now I'm wondering if it could be the lid position sensor? Any thoughts would be appreciated.
I agree. I bought a used latch on eBay, which I'm pretty sure will have the same problem. But at least I can dissect it to find out whether the built-in sensor switches can be fixed. Otherwise, it's a new latch.
The details below apply to the R231 latch, but the sensor switch issue may exist in the R230 as well.
The R231 trunk latch actuator is electric motor driven and contains 3 sensor switches (see photo). The used latch I bought had the same issue, so it may be a common problem. I confirmed it had the same issue by placing it in the freezer for an hour or so and then testing it on the bench. I dissected the latch to learn a bit more about what was causing the problem and whether there might be a way to repair a latch without opening it up.
The switch circled in the photo of the gutted latch is the one that fails -- it will stick in the ON position. This issue will usually start with cold temperatures (32F or less) and the switch may start operating again once things warm up. That particular switch is driven by a cog on a large drive gear (removed in photo) and is clearly used to tell the computer when the drive gear is in proper position. When it sticks ON the computer gets very confused and will continuously run the latch motor, or if you push the trunk close button the trunk will close and immediately re-open. Other odd behaviors can also occur all resulting in the trunk not properly latching shut.
My theory is that the cog is pushing down on the switch a bit too hard. Over time that weakens the spring in the switch and it eventually fails to spring back. As you can see in the photo the switches are packaged micro-switches and in my experience they're pretty much impossible to repair. That's especially true in this case given that they're bonded into a housing that can't be accessed without ruining the latch. I had to drill out the pins to open the latch.
To make a long story short, I had to buy a new latch. Don't trust any used latches since they almost certainly have the same problem. I'm hopeful MB has analyzed this problem and fixed the flaw in the new latch.
On my 2003 SL55, I replaced all 5 struts (2 for hood, 2 for the trunk, and one for the trunk opening for raising/lowering the top. The new struts still do not push the trunk lid up when the latch is released.
Hi, can you tell me how many Newtons are the struts of the trunk?
The struts are not designed to open the trunk or hood. After you fully open the trunk or hood, if it won't stay open then your struts are bad. The first signs of bad struts will usually appear in colder weather.
If you have the "power" trunk option then a separate hydraulic system is used to open the lid. I believe all SLs have that feature since it's the same hydraulic system that opens and closes the top.
Is part number 231-750-00-85 the latch actuator that you replaced? MB quoted me $380 labor, in addition to the $350 part (a bit cheaper online). Does that labor sound right, that it would take 2-3 hours to replace?
Originally Posted by jmattioni
The details below apply to the R231 latch, but the sensor switch issue may exist in the R230 as well.
The R231 trunk latch actuator is electric motor driven and contains 3 sensor switches (see photo). The used latch I bought had the same issue, so it may be a common problem. I confirmed it had the same issue by placing it in the freezer for an hour or so and then testing it on the bench. I dissected the latch to learn a bit more about what was causing the problem and whether there might be a way to repair a latch without opening it up.
The switch circled in the photo of the gutted latch is the one that fails -- it will stick in the ON position. This issue will usually start with cold temperatures (32F or less) and the switch may start operating again once things warm up. That particular switch is driven by a cog on a large drive gear (removed in photo) and is clearly used to tell the computer when the drive gear is in proper position. When it sticks ON the computer gets very confused and will continuously run the latch motor, or if you push the trunk close button the trunk will close and immediately re-open. Other odd behaviors can also occur all resulting in the trunk not properly latching shut.
My theory is that the cog is pushing down on the switch a bit too hard. Over time that weakens the spring in the switch and it eventually fails to spring back. As you can see in the photo the switches are packaged micro-switches and in my experience they're pretty much impossible to repair. That's especially true in this case given that they're bonded into a housing that can't be accessed without ruining the latch. I had to drill out the pins to open the latch.
To make a long story short, I had to buy a new latch. Don't trust any used latches since they almost certainly have the same problem. I'm hopeful MB has analyzed this problem and fixed the flaw in the new latch.
Yes, Lock Actuator 231-750-00-85 is for the 2013+ SL.
I bought my part online from MercedesPartsHub.com (about $260 delivered) and installed it myself. It took me about 3 hours to replace -- you have to remove all the trim from under the trunk lid to do the job. The worst part of that was the plastic trim piece covering the latch area. It's a little tricky to get off. I probably spent an extra hour figuring out how to get that piece of trim off without breaking it. Hopefully, the MB shop will already know how to do that.
11-02-2016, 08:33 PM
