Hi all

I have a 2016 GLC 300. I don't use the sunroof that much. maybe occasionally. but recently I realized that I am not able to open it. I was able to open the insider fabric shade no problem. but when I attempted to open the glass sunroof, only the right side tilted open a little then it refused to slide more. I can hear some noise from the motor. when I tried to close it, it closed completely. and I am able to close the fabric shade layer as well.

Anybody having similar issues or ideas what the issue could be? I live in southern calfiornia so there's no harsh weather. and I don't use it often so I don't think it's wear tear either. just feel very disappointed this happened.

I googled and read a lot of articles and saw a lot of youtube videos, nothing seems to fit my problem exact. for instance, some articles suggested lubricate the rail. but since I can't even open the roof how am I supposed to lubricate it?

And I do not want to spend thousands of $$$$ in a dealer for something like this. i hope I can find some guidence to dyi fix it if possible.

 

If never cleaned and re-lubricated (or worse, done by someone who used the wrong grease), it might need that -- even in sunny California, the grease dries out and gets sticky, which literally gums up the works. The safety feature stops the roof from opening/closing if it gets stuck (to prevent damage or injury).

Before a trip to the repair shop, let's make sure there isn't a sync issue first. So try resetting it -- as sometimes this happens, if it somehow "forgets" where the closed / open positions are. The is due to electrical glitches, and often happens after the battery gets weak or is changed. Usually it's just a reset for the auto open/close features... When doing this, make sure all doors are closed when you do this (perhaps not necessary, but some of the electrical reset things require doors to be closed).

Perhaps this was covered by the YT videos you found, but for the Pano Roof, it's basically pull the switch down a few times (which normally closes it from the tilt position), and then hold it in the that position for a few seconds on the final pull. Since you can open the blinds, but not the panel, then you may also need to try this a couple of times -- first do as described in the previous sentence, starting with with the blinds closed. If that doesn't work, open the blinds, and then just pull the switch down and hold until a few seconds (this second option is a single pull down and hold -- as noted above, not using the auto features).

If that doesn't work, try BOTH of above steps a second time -- really, I'm not making this up (Mercedes says you might need to do the reset twice). Remember, it doesn't meet the definition of insanity if you try something a second time, it's only insanity if you do it over-and-over again, expecting a different result....

If none of the above work, then it probably is a mechanical / lubrication issue.

FWIW, my 2006 E-Class had a rattle in the Pano roof, and two different service people at the dealer told me they would NEVER buy a car with a Pano roof. After they fixed it by removing it and replacing the trim, it worked flawlessly for the 4 additional years I had the car (I cleaned/lubed it annually myself every year or so after that).

 

Never used my pano in Arizona. Too much sun and summer heat. Had to put tint on it and wind noise was annoying. Was really glad to get no sunroof option on my GLC. Definitely not worth paying dealer to fix.

 

Hi el781,
I m encountering exactly the same issue with my sunroof, it won t open anymore because one corner doesn t lift up.....grrrrr. Can you tell me how did you fix your issue ? I would be very interested to know that. Thx

 

Hi,
Have you tried opening it manually?
You probably have a broken plastic guide that prevents you from opening your roof.
Does he rise from the back?
Have you tried helping your sunroof open by pushing it from the inside?
You have to open your sunroof and then post pictures of your rails and plastic guides, from there I might be able to help you.
Cordially

 

i d like to tell you how i ve repaired my sunroof, Simply i ve been lucky because i ve found one guy who is specialized in Sunroof repairs. He is retired from MB and 15 miles from my home. I booked a visit with him last week. It took him 3 hours to take down my sunroof, fix it and put it back up. It's technical and complicated. He changed a very small plastic part that usually breaks! I paid about 400€, it's really the price of his work and it's much cheaper than at MB. This is my second MB car with a sunroof that locks so I really don't recommend this equipment!

 

Is yours a Pano or regular sunroof? What was the little part you mention?

It's nice to find a person who is good at a specialty.

 

Hi
Yes it s nice and it should exist elsewhere...
My roof is a Pano sliding sunroof like this one https://www.ebay.com/itm/255351742714
The part that has been changed is the right rail frame glass slider guide because of the plastic part at the end that broke.
You can look at this video to get an idea about the kind of job you have to do to repair a MB Sunroof, it s tricky really

 

https://www.ebay.fr/itm/364004013161
simply as this.....

 

https://www.ebay.fr/itm/364004013161
the best solution ....

 

Mine does exactly as OP described. I haven't found anyone capable of fixing this outside the dealership so I'm not willing to fork over whatever they want to fix it. Looks like I just have a glass roof now that doesn't open. At least the shade still functions properly.

 

I have the same issue. I did some research and it’s very common on the GLA/CLA however I haven’t seen many people with the same issue in the GLC. I saw some people get quotes for $3-5k but then I also saw people only pay for a $12 part… interesting. would love the know what the issue is. dealer wants a $195 diagnostic to tell me what is wrong with it which is bizarre if it’s only a small $12 part. not so happy about this. I am too scared to push it open like someone else said in this discussion because what if it doesn’t close and then I have a convertible GLC, not so thrilled. If anyone finds a solution, would love to know.

 

Panoramic sliding roof - clean and lubricate guide mechanism

 

I'll hop in this thread as I'm dealing with a broken sunroof as well on my 2018 GLC (w/ ~90k miles...)
I'm 90% sure it's the same root cause as most of the pano sunroof issues since I neglected to do the roof rail lubrication (yeah, I know...)

I'm a DIY guy, and after reviewing a few videos on YT, it looks like it's a huge pita to do this...especially in Arizona where it's going to be 110^F today and about 120 in my garage
I really don't want to spend all weekend in the garage working on this and possibly screwing it up.

That said, I did find a local sunroof specialist down in Mesa that I'm bringing it to on Monday. He said the rails are about $350/ea from the dealer and he does recommend replacing both even though only one may be broken.
I'll update later once it's fixed with the details of how the repair goes.

Moral of the story...be sure you're cleaning and lubricating the rails of your pano sunroof before it breaks.

 

https://www.ebay.fr/itm/364331127120

 

Looking at all the threads & forums, I've designed and produced a drop in fix for similar issues that people are describing. My guide tabs broke, and I printed extras to help out the MB community.
Dropping this for help!
Let me know how it works and how I could improve it!
Works great so far in my test-vehicle; my personal w205 C63!
Cheers everyone!
​​​​​​​https://ttartcollection.com/collecti...cls-class-c257
- Axel / Axel W Photo / Ttart Collection

 

I'm having this same issue on a 2016 GLC300. I'm willing to try this part, so long as it comes with instructions. Let me know.
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​​​​​​​www.tto-pieces.com