sunedog

2012 ML 350 (W166). Sunroof (or sliding roof) will open smoothly and then close smoothly using the selector switch, but as soon as it fully closes, the rear edge opens to the tilt position. Does this every time. You can coax it down a tiny bit at a time, but it is very difficult to get it perfectly closed (no wind noise or water entry). If you go too far, it tilts fully open again.

I have looked at reset procedures in other threads and in Youtubes, but the only ones I can find are for other models that have a 4 function switch (push up to tilt up / pull down to lower from tilt /push rearward to open fully towards rear / push forward to close). This model has only a 3 position switch (push up to tilt up / pull down to lower from tilt -- also pull down to close from rear open position / push forward to close). The owners manual is no help.

Anyone have the same problem and know how to fix it?

Diabolis

There is a micro-switch that signals the system when the roof is in the closed position that has failed. Seen it happen on a C63 of the same generation that presumably uses the same system.

sunedog

Thank you! That's what I was thinking. Do you happen to have any info on replacement? Where is it located? How much will I have to dis-assemble to get to it? Part number? A link to an exploded parts list for that sub-section of the car would probably answer most of my questions. Unfortunately, I am not finding such a drawing online anywhere.

Koenig1

You know, problems like that are like your standalone computer taking a dump/slowing down/not processing! "When in doubt, reboot!!!" So.... not sure if a disconnect of power(battery) for 30 mins will work in an MB, but might be worth a try.... good luck.

Diabolis

Unfortunately not. Even if you're a decent amateur mechanic, unless you have access to WIS (not to mention that you may also need a working SD Connect C4 Mux and DAS Xentry), you're probably going to be better off leaving this one to a pro.

sunedog

I might have to resort to this. But I understand it is likely I will have to re-synchronize all the windows and the sunroof if I do this. I've seen vids on the process and it looks trivial. Just wish I could find the process to re-synchronize only my sliding roof. Remember, my model has a 3 position switch. Everything I find on the web is for a 4 position switch.

sunedog

I don't have access to WIS, but I have found some factory procedures related to sliding roof repair for other years and models in other threads. Don't even know what a working SD Connect C4 Mux and DAS Xentry is.

I'll take some time this weekend and see if I can get any trim pieces off revealing the workings. Then try to find the switch. Thanks for your help.

Diabolis

NP. The C4 mux is a mutiplexer device that allows the car to communicate with a computer running DAS Xentry (the diagnostic software). Required if you need to make any coding changes and/or reset individual modules.

sunedog

To close the loop on this, I had the vehicle in to the dealer for another issue and asked them to look at the sunroof. $150 for the first hour of diagnosis and they advised there was a stick/twig caught somewhere in the mechanism. For another $150 in labor, they would drop the headliner and remove it. I told them to go for it and they fixed it.