gircal

Does anyone know how to reprogram for automatic operation? Thank you ...

Wolfman

Not sure what you mean. It trunk opens via key or the button in the driver-side door. Nothing to program unless it's broken.

gircal

Well, it will unlatch by the section over the license plate, but it doesn't lift. The door switch
doesn't work and the trunk closing and security (on door jam of trunk) lights are not illuminated. The only way to lift it and lower it is manually and to close it manually ... it
doesn't latch itself closed.

Wolfman

Before I say it's broken, let me clarify. Is this actually a US model? If not, the powered trunk may be part of an option or package not included in the car.

Quick to check; if you have keyless-go you have it. With it, there are two buttons on the trunk lid (one to close, one to lock). Or without it at least a button (not the trunk, the lid)?

No button, no powered trunk.

gircal

Well, it reset itself overnight. So, it takes about 12 hrs to do it and now the trunk lifts and lowers when switched from the key, from the trunk latch or from the door. However, I'm
still curious why it stopped in the first place. Any thoughts, anyone? Thanks.

Wolfman

Weird. I have stopped manually while the trunk was opening, etc. Never got it to not work correctly.
You may want to stop by MB to have them check for error codes. Better have them replace stuff while under warranty...

jbattan

My 2009 SL550's trunk will stop working sometimes, requiring manual lifting. But usually by the time I take it into the dealer, it starts working again. If not, they put lube on the flaps and hinges and it gets all better for a while.

Even my 2015 SL550 stopped once when lifting the lid.

gircal

Thank you, jbatten. It seems it is normal for it to occur from time to time. I did take it to the
MB dealer (and of course, it worked) and they thought I was crazy, had never heard of it
happening to anyone else and had no idea what to do about it if there was a problem. (Same
normal MB service incompetence. They are very pleasant here, but really don't know much.)

tridge400

I am having the same issue..was working fine and just stopped ..will not open by key fob, driver door switch, or trunk latch.....what is going on?

jetjok

I had a similar situation with my 2017 SL450. The key would no longer open the trunk, and the trunk release button on the drivers door didn't work either. I brought it into my MB dealer and it worked, of course. They took it to the back and hooked it up to their computer and it came back with no unusual codes having been triggered, so they changed the key battery and sent me on my way. Needless to say, an hour later, while I was out and about, it started doing the same thing again. However, this time, I took a video with my phone and attached it to a text message, which I sent to my service guy. He texted me back to bring the car in the next day, which I did. He told me that there was a computer fix for that problem, which they applied to my car. It's been working fine since then. I wouldn't consider it normal, for that to happen at various times, and to then fix itself.

TennesseeZ4

My 2013 has exhibited some trunk handle release sticking in colder weather. I have to manually engage the trunk lock, and then manually open it again and it works fine. Only in cold temps. Probably need to move further south.

jmattioni

Just fixed this problem with my 2013 SL550 (R231). If your trunk acts up in cold weather there's a good chance it's the same problem -- a sticking sensor switch inside the trunk lock mechanism. There's no simple way to fix the mechanism so you just have to buy a new part. Don't buy a used one. I did that initially and it had the same exact problem. I ended up tearing apart the used unit I bought to find the exact cause -- a bad micro-switch. I posted more details on this thread:

https://mbworld.org/forums/sl-class-...e-its-own.html

Skip to the last page of the thread for my post.

kbob999

I’ve got the same problem with my trunk handle not opening the trunk.
I’ve taken everything apart and tested it for all functions. Here what I found...

Remote unlock works with both keys.
Driver door switch also unlocks trunk.
If you put the key in and turn to left, the lever is mechanically attached to the release, and opens the trunk.

The trunk lever normally trips a micro switch, which triggers the pump to open the latch.
Tested the micro switch and it is working, but is not sending a signal to the pump to open.

Checked fuses and they are OK. SDS shows no problems.
Must not be sending a signal from the micro switch to the pump.
Any ideas on wiring and where to trace this?

jmattioni

Your're probably aware of this, but make sure to have the trunk key lock in the unlock position. Otherwise it disables all electronic unlocking of the trunk - valet mode.

Besides that, I've heard there's a trunk lid position sensor on one of the lift cylinders. This could come into play as to whether the computer responds to the trunk release paddle switch. Not sure though.

Silver-Bullets

I've had the same problem. The trunk started to close and I stopped it mid-way to get something out of the trunk. Then the trunk started to sink and close.
The key fob, the door switch and the trunk switch work to unlock it, but it won't go up and begins to lock up again.
I've looked for a fuse to pull, but everything is pointing to a previous model SL and a different fuse box.

Would love to reset this somehow. Is there a way to do that? I've tried the 10 sec hold on the door switch to resync it but no change.
I'm wondering if the Trunk Lid Position Sensor (B24/16) is misreporting to the computer. I don't have a code reader to help out but I do have the WIS database.

My father was a mechanic and I've tried to repair all my own cars up to a point, but this one has be baffled. Any help would be appreciated to troubleshoot my trunk.

crconsulting

Looking at this thread (and another recent one) There appear to be a couple separate issues triggered by lower temperatures.
It’s important to isolate what is ACTUALLY malfunctioning. One appears to be latch/positioning related, and the other appears to be lift strut related. They are separate functions but it’s quite feasible for both parts to be affected by these lower temperatures, or a single part interfering with the others function. If the lift struts are unable to lift the trunk lid, the trunk latch then will read the trunk in the closed position and react accordingly. It’s also possible that a malfunctioning latch micro switch would prevent the trunk from opening. In which case the struts should function normally. i.e. trunk lid should open unassisted after latch is open.

XENTRY might help as it may point to an issue with the latch (or position) micro switch, but it’s also possible the lift struts malfunctioning would trigger a latch (or position) code. So in this case you’re just using the codes as clues pointing to a general area.

Silver-Bullets

Crconsulting, I agree with your analysis. This started when the temperatures were still in the 70's and the car is only 6 years old so the lower temp issue may not apply.
Since I stopped the lid from closing mid-way down, I think something has either shifted, or sent a signal that has messed up the sync. I don't hear any pump or motor sounds after the trunk is "Opened" to have the struts lift or close it.

jmattioni

If you manually open the trunk all the way and then it slowly drifts closed then the struts are bad. This gets worse in cold weather.

jmattioni

The struts in question are not powered. They're just pressurized "shocks" that help in opening the lid and keeping it open.

Silver-Bullets

Joe,

Thanks for checking in with the strut info.

If that's the case, I can check to see if they have any pressure left in them if I disconnect them to test.

crconsulting

Keep in mind, there’s a lot of leverage on those struts so they need quite a bit of force to lift and keep the trunk open. Even if they are out of spec. and weak, they may be difficult to compress. Though difficult to compress and may seem ok, they still could be too weak to keep the leveraged weight of the trunk open.

tx170754

The dealer replaced both struts with OEM ones when I've bought the car (warranty paid) w/o any success....

crconsulting

I may have missed it, but what are your symptoms?
Did the dealer scan the car when repair was unsuccessful?
As posted above, there are separate issues at play here. It’s important to isolate the different functions of the trunk mechanics in order to properly diagnose.

tx170754

I cannot say nothing about cold temp. since I do not drive the car during the winter but even in the summertime the trunk sometimes tries to open multiple times but it still stay close, so I have to manually open it. I don’t know if the dealer did scan it before replacing the struts and after. After reading about this issue I’m incline to believe that in my case is the switch, after the weather will get better I will go for an oil change to another dealer that I’m using after that fiasco and eventually ask them to diagnose the problem. And btw the replacement of the struts (which is one of the cheapest and easiest jobs ) was worth I guess around $280, total rip off even if the warranty paid for it, that dealer is history for me.

crconsulting

Sounds like a latch/switch issue. As a cheap/free fix, to see if it helps. In case the trunk seal is creating “bond” with the trunk lid, you could try and apply some Gummi Plfege (or similar) rubber conditioner to the trunk seal. The trunk has to “pop open” a little bit for the struts to work their magic. If the latch reads trunk in closed position, I believe it will latch closed again.
as jmattioni stated in post #18
Likewise if your trunk “pops open” a bit and you have to manually lift your trunk, then it doesn’t hold in the open position, this also points to bad struts…

Yeah, there can be a communication disconnect between service writer, the guy actually doing the work, and back to the customer.
To be honest, most customers don’t care. They just want their car to work properly…


It’s quite possible. One would think they (dealer) would scan the car to see if any codes are stored for the trunk area too.