Been having on-going roof problems with SLK that bought few months ago,
have read all the posts on the forum and have posted a couple of times.
Over last few months have managed to build up a picture of when and what
goes wrong and more importantly what resolves it.

The conclusions so far are that when roof hasn't been used for a while then
it will tend to go down fine and then won't come back up, the boot will open
but nothing - what is strange and what seems to separate it from other
peoples problems if I just sit there and do nothing then after a few minutes
it will work fine (sometimes just 1 minute). Sometimes again when hasn't
been used for a while it will not go down - again boot opens but nothing, again
just doing nothing or trying a few times will resolve the problem.

Have managed to get it into a mercedes garage when it has been in failing
state and they put the diagnostics on it and they have checked all the
switches are operating as they should (thought it would be the boot one
when first got car and read FAQ posts). They saw same thing that after
trying a few times and then just leaving it standing still it started
working.

So question is what could it be if not switches, the hydraulic level has
never dropped and all pumps sound good. They replaced the relay (all free
of charge) and only thing they can come up with is there is some air leak
or something on one of the rams and leaving it a while (sometime a minute
sometimes 5-10) allows it to build pressure back up and then work - not
convinced myself and wandered if anyone has had something similar. What
they want to do is take all the panels off and operate it whilst monitoring
the rams but this is where I am going to incur my first outlay and not
convinced. Forgot to mention on a previous visit they did re-lubricate
the mechanism.

It's an old SLK (1999) but is low mileage and don't really want to spend too
much out on it, just wish could find something conclusive that fixes it.

Any suggestions greatly appreciated.

Lawrence

 

OK, key question.

When you say the roof will go down but may not close again unless left for a minutes etc. you have not been clear on exactly what happens/doesn't happen.
OK the roof doesn't raise BUT is the pump running, do the rear windows drop, does the red button flash etc or do you imply that NOTHING whatsoever happens when you move and keep the operating switch in the required position?

IF absolutely nothing then this suggest that the problem is upstream (power supply) whereas if the pump starts, window drop but the roof stays put then it points to downstream i.e. the vario system itself.

The garage seem to want to remove all the boot trim etc which is quite resaonable if indeed the system is partially working (you can DIY quite easily...no special tools...) but if it is indeed a supply issue i.e. poor contact within the fuse box that gets warm and then cools etc removing the panels would not be next on my list.

On re-reading your post you state that the boot opens but that the roof doesn't move. If this is correct then this suggests that it is in fact the limit switch that senses that the boot is in the fully open (reverse) position. The pump and supply electrics must be OK to get this far.
If indeed this is correct then does the pump noise change as the boot nears/at fully open or does everything just go quiet when the pump stops.

You implied MB did an SDS Star Quick check and that doesn't reveal ANY codes. SDS usually manages to identify some codes even if not relevant to this problem. Not sure they have done an SDS. Did they give you the print out?

Clarify issue and I'll advise what I might do next if I were experiencing your problem.

Since you are the new owner of this car it is possible that the vehicle has had some form of rear end accident. Is this possible / likely / or can it be ruled out?
Check paint condition. If its a 99 it should be showing at least surface scratches and some rust around the underside of the rear arches.

Stuart

 

Thanks for your reply, the roof when stuck up or down (more usually down) the boot will
always open and then go no further. Holding the roof button the pumpsrun and make same soundas if all were working (quarter windows do as they should). Then sitting there for a
minute sometimes five and trying again it will magically work but it does always need a
pause - just keep holding the button to try and get it to come up or going back and forward
when the roof is down - ie getting the boot to close and open again doesn't seem to do it,
sitting there with everything completely shut for a few minutes and then going again
does it. I used to think it was me getting out of the car and fiddling with things fixed it
but last few times I have just sat there.

The mercedes garage have run the diagnostics twice on it, the last time when it was in failing
state. As you suggest it did show up loads of minor code but assured nothing to worry about
and nothing to do with the roof - I did get to see the print out.

Pretty sure the car hasn't been in an accident - the car is really low mileage and been
garaged all its life but does have the odd stone chip and mark to tie with it's age.
The roof on occasion - in fact more often than not does work perfectly - it seems the
more use it gets the better it is which is part the reason they re-lubricated everything.
The garage have not seen anything like it before as normally turns out to be a switch
that shows up or a hydraulic leak - the level on mine has stayed the same throughout.

 

Been there and had that problem.

'99 SLK 230K, only 38,000miles on it with previous lady owner.

My dealer tried a few times to pin it down, including chenging out a relay in the tail due water corrosion. Didn't fix it either. The problem is the wiring loom that runs up through the roof. Think how many times that loom has had to bend one way then the other as the roof operates.

I changed mine, and the front catch switches at the same time, and that fixed mine. The loom plugs in under the trim in the right side of the boot/truck, and runs up the right side of the roof into the main roof itself where it's clipped in and locates on two switches. Not a difficult job but takes a couple of hours. You'll need snips and a bag of ties too.

 

Hi,
Never had any problems with a vario roof but maybe I can provide some assistance from my sketchy first principles understanding.

There are 5 key electrical sensors in the system.
1. Roof "Closed" located in the windscreen header rail S69
2. Roof "locked" located adjacent to the latches in the roof panel S69/3
3. Boot (reverse) "open" located on hydraulic rams operating the tubular frame that opens the boot. S119
4. Boot "locked" adjacent to the latch located on centreline of car behind rear trim S3
5. Pump over temperature sensor mounted on motor. Not sure if this was fitted on R170.

All of these would show up on an SDS check if there was an ELECTRICAL continuity / plausibility issue.
As a consequence I do not believe that the wires that navigate the RH hinges into the roof panel are at fault. These are quite pliable since they are only signal wires and they signal that the roof has gone fully home and locked. Nearer the boot the harness also carries the heavy duty rear window wires which if routed incorrectly may be more problematic.

As I understand it R170 (your model) uses a cord mechanism to operate the roof latches from a remote hydraulic cylinder in the boot.. As I understand it these do give problems due to snapping if the latches become very stiff etc.. R171 was improved and uses hydraulic actuation within the roof space rather than remote in the boot.

If the roof latches don't operate, to allow the roof to move, then the sequence will fail at a point similar to that that you are experiencing.

Suggest you remove the headlining and observe the operation of the roof latches during the sequence. Do the latches try to operate and have become stiff, cord broken or whatever. Follow the cords to the hydraulic ram. If the ram doesn't operate as required I suspect you are back to the sensor that senses that the boot is fully open.

Since the problem is intermittent I still go for the "adjustment" / intermittent connectivity of the boot (reverse) open sensor on the hydraulic ram. This might not show up as an electrical fault (switch works OK) but due to incorrect adjustment doesn't provide the full limit signal at the point required so the valve block doesn't receive the signal to open the roof latches etc.

Hope this helps. One day i might get around to looking at the trouble shooting chart in WIS!

Stuart

 

Normally a rear sw behind r/h tail light. Cables to roof sw(s) also go open but from my exp only affect initial opening.
Run a jumper across rear sw wires conn to a push on sw and press when fault happens to prove out switches.

 

I have replaced my leaking roof cylinders at $2500 a year ago before I knew about Martys kits.
Now the boot rams - the ones that open the boot / trunk are leaking.
Martys kit instructions say they cannot be fixed and they are $800 each plus labour to replace.
I'm almost resigned to running with the roof up forever which is a pity since it happened after I bought chrom roll bars.
Does anyone know someone that can fix the rams or replacements that might be cheaper?
car is R170 model

 

still with the roof on the SLK 230, I still wish to know where the three wires from the boot latch micro switch go to.
I thought it was just an earth to the control module which would only have two wires?
now getting itchy