I've just watched a video on YouTube on how to close the roof manually. It would be impossible to do it on your own or for that matter with a assistant. So my question is how reliable is the system. May be I'm being paranoid but after watching said video I would be reluctant to lower the roof again.

 

After three SL’s and years on this forum I do not remember anyone reporting a problem with the roof breaking in the down position.

If it happened to me I would drive to somewhere covered from rain and call AAA and have the car towed to the closest dealership.

 

We had one roof issue due to a locking sensor in the A-pillar. Brand-new 2017 model. Minor issue and due to a less than perfect adjustment at the factory where the lock would engage or sometimes not.
The only SL known for roof issues were the R129 soft top roof two to three decades ago and the older R230's if the flaps failed but for a complex mechanism these are pretty rock solid.

 

Thank's to you both for your prompt reply's

 

Can you provide any more details on the specific sensor that caused the roof problem on the 2017 you reference? I am experiencing intermittent issues opening my roof. A message pops up on the dash display indicating "servo roof is operating" but the roof does not open. I can hear mechanical sounds from the trunk that something is moving but the roof does not open. Occasionally, I can get the roof to open occasionally by alternately raising and lowering the roof toggle in the center console. The "fix" is to get out of the car, open the trunk, cycle the luggage cover, return to the driver's seat and then the top will open and retract into the trunk.

Never a problem closing the roof, only when occasionally when opening.

This does not happen all the time. Usually, if my 2017 SL has been in my garage, I can usually raise the roof toggle and the roof will open and retract on the first try (but not always). Seems like if the top is in the up position, and the vehicle has been outdoors (in the heat) for a couple of hours, I will frequently have difficulty putting the top down. I then resort to the manual opening and closing of the trunk (as described above) to put the top down.

I have discussed this with MB service. They have never been able to recreate the problem even when I leave the car with them for several days. Would love to hear from any other R231 owners who may have encountered similar issues and how you resolved the problem. I suspect it is one or more micro proximity switch that all need continuity before the top can open or close. I don't have any idea how many switches are in the continuity circuit or their location.

 

Just saw your post. This happened in 2016 when the car was brand-new and I will look for the service ticket for details over the weekend. But I know it was related to the small micro switch (faulty or poor positioning) of the passenger roof lock on top of the windshield. Was a quick fix except the idiotic tech broke the windshield in the process

 

I'm thinking that if you have something moving in the trunk and the roof is not opening, it might be that the luggage divider is not properly moving into the down position. I have this happen if the car has been sitting for a week or more without being started, and it seems that the luggage divider sometimes binds or reverses when the battery is a bit low.

My solution has been to always open the roof with the engine running. I let it idle for a minute or so, and then give it a little gas to bring the alternator power up a bit before operating the roof, and I have zero problems if I follow that regimen. Worth a try to see if that helps!

 

Thank you. That's certainly easy enough to try. I definitely have been attempting to open the roof almost immediately after starting the engine. Most frustrating problem is that it is intermittent and often difficult to duplicate when troubleshooting.