NixFix

Hi All,
I recently purchased a 2017 C63S Edition 1 Coupe. The seller failed to disclose that the sunroof didn't open (I know, should have asked and checked). Now that the water is under the bridge, I am attempting to fix this myself...

Background:
When attempting to open the sunroof, the FRONT will lift and then subsequently go down. I assume this is due to the rear not lifting before hand, triggering an error and putting the sunroof back to the 'safe' closed position. I am a very avid DIY-er and have done plenty of projects myself before (engine and transmission replacements, clutches, brakes, suspension, subframes, etc.) to which I consider myself an experienced wrench. So I do think job may be within my scope of capabilities. However, this is my first German car.

Currently: I am at the point of attempting to manually open the sunroof - I have gotten to the sunroof motor and am attempting to open it by twisting the 4mm hex input inside of it. Where I am getting suck is that the rear will NOT raise. I tried with some plastic pry tools wedged on the outside and working it back and forth... no luck.
I pulled a buddy into this to see if he can push up while I twist - no luck either. I am faced with extreme resistance at the motor when attempting this, to which I assume is where I should not torque any further.

Overall Objective:
Does anyone have any advice or tips for opening a sunroof/panoramic roof that is stuck in the CLOSED position?
I already have the replacement parts and just need to physically open the roof to access the rails. Also, in terms of programming, I have that covered too (aka I am trying to avoid the dealership at all costs).

hotdognobun

Did you do the calibration/reset where you hold it forward for a few sec then back for a few and forward again then back one more time all within 5 sec for each?

Wolfenhaus

Highly annoying, but I guess it's better than it being stuck in the open position.

NixFix

Yes I did - unfortunately I am at the stage of replacement now. This is one area I really wish Mercedes didn't cheap out on.

AndreF213

I am currently in the exact same situation as you. I'm a tech myself and trying to fix my sunroof in my 2017 C300, I have my head liner fully removed, I have messed with the motors, removed the motor and even tried to use a pocket screwdriver to push the one side of the teeth that the motor contacts. while having someone lift from the inside, glass won't budge and from what I can see you can't remove the glass or rails without the glass lifting up. Did you happen to figure it out? I'm about to just give up on it and put the head liner back in, only way I see this happening is by breaking and replacing the pano glass.

Any advice would be appreciated.

hotdognobun

Do you hear any kind noise from the motor when you activate it? Wonder if it's the fuse so check the voltage location to see if there's even power going to it?

AFord213

Sorry I wasn’t that clear, motors for both shade and pano glass are functioning with voltage, switch for sunroof and sunshade are functioning. One side of glass lifts the back corner. From what I’m gathering it is the guide rail OR some little plastic clips that are broken. The run roof motor will only lift one side and then will go back down. I removed the motors to mess with the actual mechanism but it does nothing, feels the cable is not attached to the glass on one side and the glass is unable to be lifted to be unscrewed.

What I’m wondering same at the thread opener is, if there is a way to manually open the pano glass with one side being stuck closed.

nougat

I am having the exact same problem (glass will partially open and lift on one side but not the other and then close itself) and I have tried having one person push the stuck side up from inside while another pulls from the top using a glass suction cup. It will not budge. I feel like it will break something more costly if we apply any more force, although the MB dealer quoted me $4,500 to replace the rails so I'm not sure how much more expensive it could get.