w126 sunroof jammed + Instrument cluster removal

[vitasik]

Hi everybody.
Two days ago i opened my sunroof and when closing - something went terribly wrong. Result is: my sunroof is in place, but one side is not lifted to completely close the sunroof. Additionally mechanism inside roof is working(sliding back and forward) but it has lost all mechanical connection with the sunroof itself. One part was broken and just laying there when i lifted slightly the cover to see mechanism. I can repair the part, but i am not sure how to get to this mechanism. As a good starting point- is there a way to remove the sunroof cover (part of the upholstery) that slides with the glass?

Any suggestions?

Additionally when playing with it during weekend i would like to remove the instrument cluster as my tachometer is not working, but i couldn't see any screws/bolts for it.

Help here will be much appreciated.

Thank you

 

[khimani_mohiki]

I have just been through the same thing with 2 broken mechanisms. You need to open the sunroof in order to get the interior panel out without damaging it, if you cant open it due to a jammed broken mechanism you can pull the panel out without doing too much damage to it, mine bent but it was easily bent back in to shape.

 

[219]

Cluster removal is really easy - I use the can opener attachment of my Swiss Army Knife : insert blade in at the side of plastic cluster between hard plastic and padded surround , twist slightly and hook in behind edge , pull gently . Alternate between one side and the other going carefully until cluster comes loose . There's enough cabling to allow it to come out far enough to disconnect - problem may just be a connector off .

Make sure steering wheel more or less level and cluster will just slide out above it - no need to remove wheel - done it lots of times .

Re sunroof - as above - get trim off , pops down along front edge , and hopefully fault should be apparent .

 

[vitasik]

Thanks.
Tomorrow is definitely play time
Will post after successful removal.

P.S. Just remembered that i have service manual for phase 1 w126 somewhere on the hard drive ( Aint easy to find a pdf in 1.5 TB hard drive) .

Thank you guys again. have a nice weekend

 

[vitasik]

Okaaay
I just removed the trim of the sunroof - at least 3 broken parts . Bad.... very bad.

The worst thing is not getting why i still cant open the sunroof. Additionally on one side i did manage to get up and down, but not on the other. Than from looking at the back - i can see one slider move forwards and backwards but it is not attached to the sunroof.where should it be attached?

Next weird thing is the small bore pipe ( probably end of cable) in the center of the slider. this thing remains stationary- should it remain stationary as it is attached to the trim of the sunroof?

Any comments?

P.s. Its typical English weather now so i will stop playing with the sunroof for the minute, but will remove instrument cluster and try to repair the broken parts of the sunroof ( 2 of them managed to remove as they were not attached . - its a funny thing i will post pics of later. It looks like a retainer of some sort for the trim. made of 2 bits - aluminum and plastic. aluminum is broken and it looks as if for quite a while so it shouldn't be an obstacle for the sunroof moving as it was working a week ago.

 

[khimani_mohiki]

is it an SE or an SEC as the slide mechanisms for the SEC are twice the price of those for the SE.

There is some useful info here SlideLift Roof Repair

 

[vitasik]

Thanks for the reply

its 500SEL
I can repair the parts that i have.( I am graduating Aeronautical engineering so i know my way around stuff)

Hopefully i will not need to buy any parts. My principle is like this: if it has failed there - its a week spot. Time to improve the design

Cheers

P.S. Does anyone know how to check RPM signal for tachometer? I have removed my instrument cluster, but unfortunately its not what i was hoping for - 12v wire is healthy. I do have Oscilloscope, but probe cable was borrowed by a friend two weeks ago, and was never returned. Guy is not in uk for next month so idea of using oscilloscope is down the drain.

 

[khimani_mohiki]

if they are as broken as mine were you might as well just replace them, around £26 a side i think. check with Mercedes manchester they seem to have quite a lot of discounted old stock, I got mine from them half price through Parts Reunited.

Check your flaps as well, the rubber flaps either side of the sunroof panel. Mine were deformed causing them to get stuck when i tried to close the roof, I think this may be what caused the mechanisms to break.

RPM signal is generated by the ignition controller, it can be check at the diagnostic socket, not sure how it is distributed to the instrument cluster though.

 

[vitasik]

Thanks
I will check for new parts.

About RPM- i know where signal is generated, but the question is - is it there ?
I was thinking about how one would just check its presence.

My thinking: i used my multimeter in ac mode and got the reading of 6.4 volts with very very very small difference through the rpm range. I was thinking it might become higher with higher revs. I was wrong. Presence of this 6.4v suggests to ne that there is something , but rev counter doesn't pick it up. so its either my theory is wrong or tachometer is toasted.