I'm working on a UK RHD W208 CLK 230 from 1999 and I've learned a lot from posts here but I seem to have something a bit different.

Problem:
Pull the switch and the windows drop, bow lifts, cover lifts - and that's it!

If you manually push the cover down, pushing the switch drop the bow and locks everything up again

Diagnostics:
No access to Star/Xentry but our generic diagnostics can read codes and SOME data (but no references to limit switches or anything useful like that!)
It came to us with a B1000 (which is a module failure?) but I cleared that and it's not returned
When it 'stops' it sets a B1650 which is a watchdog switch timeout BUT our diagnostic cannot read the subcode so I don't know what it's upset about.

Testing
The infamous left-side 'bow' limit switch is attached and the values at the module are correct as you move the bow manually

The cover limit switch is also attached and the values are correct at the module

I also checked the switches in the rollover hoops (as they are subcode 00 which is what our diagnostic shows) - they are AOK also

Observations
Once the cover is up it should fold the bow down - this is the point of failure BUT it CAN fold the bow down (as you can close the roof up again - see above) so it's not a pump/pump valve/cylinder problem

There is a fair bit of leakage from the left-side 'bow' cylinder - but it opens and closes just fine

The only other thing which seems amiss is that the 'cover and bow lock' sometimes sticks and CLUNKS when it's working - but obviously we're WAY past that point when the roof stops.


Solutions?
I'm out of ideas - at this point my guess is the module is faulty (the B1000 code) and just isn't getting into 'Step 7' (drop the bow) due to some internal fault

Unless anyone has any ideas we'll be packing this one off to the local specialist - however they have a multi-month waiting list and when I described the fault they seemed "not that keen" to look at it so...#


Thanks in advance!

 

Had the same problem with my CLK 200 - 2001 Reg. Checked all electrics All OK. Problem was very low oil in the hydrolic system that controls the roof.
Topped it up with the correct oil. "BINGO" all working perfect. Loss of pressure and oil level drop, was due to a Roof Ram weeping oil under load. To get at
the problem, you will have too remove the bulk head carpet at the rear of the boot. Then remove the black metal panel that covers all the roof working parts.
Not an easy job.

 

Thanks for the comment - I will check this ASAP!!

Luckily someone had already been "into" this car before it arrived so all that was already stripped down - easy life

Thanks again

 

I got into this today - oil was a BIT low (about halfway) but topping-it-off does not change anything - opening the roof still gets you to "bow up, cover up" and then stops dead - putting the cover down manually you can then close it all up again but it's going no further "open"

I manually opened it to see if it would close from "open" and nope - it's weird, it doesn't even TRY to move the bow down - if I had to guess I'd say the control box is knackered tbh

 

Question. Will the Boot open with the Fob, from inside the car. Or just the key. If you have a faulty "Interruptor Switch Part A 208 820 10 10 on the Boot Lock. A Boot Open message is sent to the system.
This will stop the roof working.

 

Boot only opens from key/switch/dash when roof is fully closed- as it should - a boot switch fault would prevent ANY roof movement surely tho (it would already have banged the cover into the lid otherwise!)

I've now been through the entire WIS checklist for this fault (Bow fails to lower or lowers slowly step)

Windscreen Rail switch - AOK at the module
Rollbar upper and lower limit switches - AOK at the module
Bow limit switch(es) - AOK at the module
Cover limit switch - AOK at the module

Only the last one is 'novel' here - all the others are checked at the previous steps so I'm fairly sure the module isn't "seeing" that switch - no corrosion outside the box but perhaps inside (it's 27 years old and has spent the last 4+ unusued!!)

It would be lovely to see what Star/Xentry has to say about this but i don't have access to one so it' s off to someone who does - maybe it will show the module 'not seeing' that switch - our diag doesn't understand the datastream well enough to be sure

Thanks for the help!

 

Hi, do you have any updates on this? I have the same kind of issue, bow up then nothing. All my micro switches check out at the switch side of the connections. I haven't found any docs on the top computer's connections. It would be "easier" to check from the computer's connector but...

My issue started after installing some rebuilt cylinders. It's definitely not the cylinder's fault, but strange that all of this started with a cylinder replacement. I did disconnect the battery to replace it, which is a possible hint, but nothing electrical was touched other than terminals off battery out, new battery in and terminals on. An electrical interruption would not of messed with the limit switches. Is there a doc stating what and where/when the switches open and close? Anything that can help diagnose the issue with my top?

 

The customer took that car to a specialist and I've not heard from them since

One weird thing tho, I tested the roof before it left and the bloody thing worked ONCE - that's one time in a whole week of diag and testing - it stopped working immediately thereafter and so I'm still of the opinion the module was toasted.

Have you checked the fluid level - if it's too low OR high it will stop the roof at key points - air in the system would also do that..

You might also was to see if you can find a Mercedes Workship Information System (WIS) virtual machine download - shady corners of the internet usually have one available - the docs aren't brilliant but there's a proper checklist, pinouts etc. etc.

 

The fluid's topped up and what's frustrating is the roof was perfect before I replaced the two driver's side cylinders! I'm guess that I may of hit a swtich or connection of offended the MB gods somehow. I'll seek out a WIS, thanks, I forgot about those.

 

Try cycling the system a few more times. I replaced the seals in my cylinders and there is air that needs to bleed out. I don’t remember exactly anymore, but it took 2-3 cycle attempts before it operated due to air entrapment.

 

Thanks, I'll give that a try today before I start tearing things apart!