Hi there,

Can anyone help? I'm sorry if the answer is already posted, but most of the posts are a few years old and I believe that I have read all of them in the last 3 months!

My 2001 W208 CLK 320 convertible roof stopped opening back in July and I have been fault finding since. One fault that seems to have developed (and it could have been since I have been opening/closing the roof manually) is that the rear bow lock mechanism which is normally operated hydraulically, but manually just now by an Allen key, will not lock without being given a “kickstart” with a screwdriver pushing against the latch mechanism. It simply will not turn with the Allen key, although it will unlock all the way with the key.

I have removed the cylinder and lock (P/N 1247700426) and can see no obvious damage or reason why it would bind in this way.

Has anyone seen this before, and if so, what is the solution?

I’m now in the situation where I cannot lock the rear bow and use the car in the rain! I’m getting desperate!

Thanks for your thoughts and advice.

Cheers

Pauldy

 

Hello Pauldy,

Our A208 rear bow lock assembly, which consist of a latch and actuating hydraulic cylinder, as was used to lock the rear bow in the former W124 E class cabriolet and the front bow in the R129 SL class roadster.

In both the W124, R129 and today in our A208, the operation of the latching mechanism (P/N 1247700426) has proven to be extremely reliable and the underlying culprit for not locking properly, was it's malfunctioning hydraulic cylinder (P/N 2198001672).

The provided provision, to manually unlock the latch to raise the roof in an emergency, is used long term to manually open and close the roof, the latch mechanism can lockup.

When that occurs, you'll find the procedure to free up the latch, at the 7:25 through 7:50 time mark, in the instructional video at:

https://www.youtube.com/watch?v=tu16...olj47fLed1joK8

Additionally, note that in order for the latch to fully close, the cylinder's rod also must also fully retract. However, because you currently have your assembly on the bench, without hydraulic system pressure being applied, you may not yet realize the underlying malfunction.

When the hydraulic cylinder is pressurized at it's nominal pressure of 150 bar (2175 PSI), the direction of motion depends on whether the pressure is applied to cylinder's piston or rod side. Additionally, when pressurized on both sides (e.g. piston and rod), the rod will also extend, because the force acting acting on the piston side is greater due to the larger active area.

It's well known that the internal seals MB used have a service life of 10 - 15 years and that the internal seals in the latch cylinder frequently fail. When the rod seal fails, you will see external fluid coming out from the rod's shaft. The other end of the rod is attached to the piston, that slides through the cylinder, sealing the sections from one another. A failing piston seal can swell up and make it very hard to move the piston inside the cylinder and eventually disintegrate and lead to blockages in the system valve block. Diagnosing internal seal leaks is well beyond the skill set of DIY as it requires both specialized equipment and knowledge (e.g. supplying hydraulic pressure to specific cylinder sections while plugging off others etc.).

The vast majority of shade tree DIY mechanics have resolved their bow locking issues by having their cylinder properly rebuilt by Top Hydraulics who will replace all of the seals (e.g. rod, piston, gland and port), using superior seal materials, for $45.

https://www.tophydraulics.com/w208-c...odel_year-1998

While not conclusive, I hope you will find this discussion helpful.

 

Hi Serndipity,Thank you so much for this information. I have delayed responding to you until I was able get the time to view the video whilst having the cylinder and latch in my hand.

I have followed the video and am able to free up the latch as instructed. However, once free and I lock the latch and then use the allan key to open the latch should the cylinder's rod be fully extended (Almost half a turn of the key or about130 degress) or only extended about half way (about 1/4 turn of the key or 60 degrees)? If it's the half turn, then it seizes up again.



I have read your posts and those of Top Hydraulics (which have enabled me to get as far as I have!) and understand that the cylinder seals have a limited life. However, there is no sign of any fluid leaking anywhere!



I'm not sure if this is relevant, but I have also found the the two tension cables that run from the rear bow to the front are both broken, and it is likely that one has been broken since I got the car 15 years ago!!



Thanks again, your information is excellent and without it I would have given up!

Much appreciated,

Cheers
Pauldy

 

Hello Pauldy,

There's a lot to digest, within the short 25 seconds, where Klaus explained how to free up a stuck locking latch, from it's open unlocked position to it's closed locked position.

The video byte begins with the latch in it's open (unlocked) position,with the cylinder's rod will be fully extended. Then he showed that when the 5mm Allen tool was unable to turn the latch mechanism, from it's open (unlocked) position to it's closed (locked) position, before you simulate the striker (which is located on the roof's rear bow) hitting/pushing (down) on the mechanism. Once the mechanism is actuated, you'll be able turn the latch to it's closed (locked) position. If all is good, as latch moves to it's closed position, you'll hear 2 ratchet clicks (provided by a pawl and torsion spring) and the cylinder's rod will fully retracted.

While neither conclusive or definitive of your underlying problem, I previously noted that the latch was quite reliable, but a fairly common issue with the A208 rear bow not locking properly, has been internal seal leakage within the hydraulic cylinder. You'll see external fluid leakage if the rod seal fails. It begins as a minor leak and worsens to where, when the tonnaeu cover opens, fluid spills and puddles into the cover compartment or onto the trunk (boot) lid. Additionally, as previously explained, if the piston seal swells or disintegrates, you won't see external leakage, but cylinder's rod likely will not retract and lock the latch.

It appears that the last time you closed your roof manually, the rear bow striker wasn't fully into the latch and pushing down on the mechanism that's required for the latch to lock.

 

Hi Serndipity,
Thank you for your excellent reply. I have now reinstalled the lock after following Klaus’s video and your very informative clarification. All was good as I heard the 2 ratchet clicks and the cylinder’s rod was fully retracted. So thankfully the rear bow is now water tight as we are now having torrential rain!
However, I still have to complete the fault finding and fix the roof!
There is no evidence of external fluid leak and the pump reservoir is filled to the maximum level, so from your comments it seems likely that the internal piston seal has swollen disintegrated.
In your experience, is this the most probable cause of the roof failing, given that I have checked the relays, and the micro switches on the rear bow and the trunk luggage screen?
The case cover lock seems to be OK, with no external fluid leakage.

I would appreciate any further pointers or guidance.

Thank again,
Cheers,
Pauldy

 

Pauldy

Whenever the power roof opens or closes, the soft-top system is controlled by an operation control module, that cyclically evaluates the status of a dozen or so position/limit switches.

If the module sees that a switch has not properly actualized, further progression of roof movement will stop.

My suggestion, would be to open the power roof, making sure that the pressure relief screw you turned for manual roof operation, has been turned back (clockwise to the stop) to restore full hydraulic system pressure.

If the roof stops before opening, refer to the below document which shows the key stages of roof operation and report back, as this will isolate where your malfunction is occurring.

Note: Thereafter, you should still be able to then re-close the roof hydraulically by using the center console operating switch.

Also, the control module has a builtin self test capability, which can diagnose some system faults, as shown in the next document.

 

Hi Serndipity,
After the wettest October on record we have a fine day and I was able to get back to the problem.
I am following your advice and reporting back!
I closed the pressure relief valve and tried to power the roof open. When the front latch was unlocked the windows opened but nothing more happened. The S84 switch flashed at 1 hz while pressed. I checked the rear bow latch and it was still locked with the piston fully retracted.
So it got as far as Stage 2.
I then checked against the second document as follows:
A. Continuous illumination when switch pressed - only during the first condition- during soft top opening operation or trying to open.
B. Continuous illumination when switch is not pressed - during the first condition- for 1 sec following ignition on, and the third condition- when soft top not properly locked (front latch open)
C. Lamp flashes when switch pressed - when vehicle operated and soft top not locked and when attempting to open soft top by pressing switch S84, when trunk lid was open at 3hz, and when trunk partition was not closed at3hz.
D. Lamp flashes when switch is not actuated - when vehicle is operated and soft top is not locked.

Does this make sense to you and shed any light on the next step?

I really do appreciate your help on this!
Cheers
Pauldy

 

The vast number of A208 roof/roll-bar issues have been successfully resolved, for short money, only using the documents that shows the critical stages of roof operation, that the controller cyclically evaluates, when opening or closing the roof. Note: This is same technique that the MB SDS diagnostic software uses (e.g. evaluates the actualization's of the position limit switches as being plausible).

When you tried to hydraulically open the roof, the controller is either not seeing that everything in stage 2 has successfully occurred or there is an improper switch actualization during stage3, that is preventing the roof operation to proceed.

In addition to the document showing the key stages involved when opening the roof, the below document shows the required switch actualization's, that should occur by the end of each key operation stage.



Additionally, here is the pin-out diagram, showing the signal connections, on the controller's 55 pin connector.




With the 3 documents, you'll be able to check all of the switch actualization's at any of the key stages of operation.

With the ignition off, disconnect the 55 pin wiring harness from the controller. Note: The diagram shows the pin-out with the connector mounted on the controller (e.g. when the wiring harness disconnected, the left to right pin orientations will be reversed).

Using a multi-meter, set to measure ohms, check/verify that the off of the switches are being properly actualized, at the stage where roof operation stops. When a switch is actualized (e.g. shown as a 1 in the diagram), the switch will be switched to vehicle ground (e.g. read as 0 - 5 ohms by the multi-meter ) or when not actualized (e.g. shown as a 0 in the diagram), the switch is not switched to vehicle ground (e.g. read as greater than 20K ohms by the multi-meter).

Your prior concern was around whether or not your rear bow was functioning properly.

However, your roof is stopping at stage 2, check and verify that each of the position/limit switches is correctly actualized (e.g. by a 1 or 0) within stage 2.

I suspect that either the S83/5 rollbar retracted switch may not have triggered to vehicle ground in stage 2 or there is a switch in stage 2 or 3 that is incorrectly being switched to ground, when it should not be (e.g. one or more position/limit switches can lose their correct sequence (e.g. incorrect triggering state) when manually manipulating the roof.

All of the roof's position/limit switches can be re-synchronized by manually opening the roof completely, followed by closing the roof completely.

Then restore full hydraulic system pressure, raise and lower the rollbar hydraulically and try opening the roof again.

If it again stops at stage 2, or a subsequent stage, you'll be able to disconnect the controller harness and identify the culprit.

 

Thank you Serndipity!
I really appreciate this. The car is currently in the garage for some repair and maintenance, so I’ll get on to this once I get it back. I think I understand now what I need to do, but I’m a beginner when it comes to autoelectrics!!
Stay safe,
Happy Thanksgiving
Pauldy

 

hi, I had similar problems with my W208. It may be worthwhile to check all the wiring loom connectors located along the inner sills and behind the rear seat backrest/side panels. Any oxidization of the contacts can cause problems. Same goes for the controller and associated fuses/relays.


Regarding leaking or seized roof hydraulic (black) cylinders, I dissected a "guinea pig" cylinder I got from ebay and discovered how it was originally assembled, It certainly wasn't designed to be taken apart! Anyway this knowledge allowed me to remanufacture my own cylinders (5 off). I made new hard chromed piston rods (OEM ones were badly corrosion pitted), and fitted all new Vitol seals (much better material than the OEMs). I hydraulically pressure tested them to 200bar and no leaks. Anyway I hope I'm not treading on the moderators toes by suggesting if you or anyone needs their cylinders remanufacturing, give me a shout.

kind regards . joe

 

Hi Joe,
thank you very much for your advice. I have not been able to get back to the problem solving since Serndipity gave me his extensive guidance back in November, due mainly to bad weather.
Despite being a rank amateur at autoelectrics I do plan to get back onto it as soon as I can, so I will be following your advice. However, there is a part of me that says I should take it to MB dealer to plug it into their diagnostics system and see if that would get a more conclusive diagnosis. Not sure it’s worth it for a 20 year old car with 100,000 miles on the clock!
Thanks again, I really appreciate it.
cheers
Paul

 

Hi Paul, yes a STAR analysis may help. If the bodywork is corrosion free which is rare for the W208, I would hold onto the car. They are increasing in value. Kind regards, joe

 

Hi Joe,
Thanks for that! Apart from a dint in the drivers door when in a car park last year and minor corrosion around the wheel arches there is little corrosion. Although it did need a bit of welding at the MOT in December to rectify “Nearside Front Suspension component mounting prescribed area excessively corroded”. So it’s covered now until 30 November 2021.
cheers
Paul

 

Having spent hours with a lot of excellent help from Serndipity and Top Hydraulics I finally caved in and booked in to MB main dealer for a Star Analysis in February. However we had heavy snow and couldn’t move the car so rebooked and the earliest was April. I had already removed the internal carpet for my own fault finding and the rear angled panel covering the hydraulic pump. In preparation. However since it’s a few weeks since I last did anything with the car I wanted to check that only the minimum number of bolts were installed to minimise Workshop time.
To my surprise, after starting the engine, I pressed the roof switch and it opened and the rear bow folded into the boot/trunk. Since the trunk luggage screen was not fitted it would not open further and I had to close it manually. I refitted the trunk luggage screen then tried to open the roof again, and it worked, opening fully. It closed normally.
what has changed? I don’t know.
From the start the rollover bar head restraints were in the lowered position and would not raise at all. Today, when I pressed the switch they raised and lowered accordingly.

Any ideas.
Should I cancel the Star Diagnostics session with MB?
Thanks for your thoughts,
cheers
Pauldy

 

Hi again Pauldy,

Thank you for the appreciations always expressed and if you need how to remove the rear seat-back (see below discussion ) and should you need to remove your rear seat-back,Top Hydraulics has also included a D-I-Y, within one of 13 A208 (cariolet) D-I-Y chapters.

Sounds like you decided against proceeding with a D-I-Y repair.

After reading your most recent update, understood after your Winter update, which updated discloses that from the beginning of your malfunctioning roof operation back in October, additionally your roll-bar was also malfunctioning.

By design, whenever the roll-bar is in an extended position, to prevent impairment of the soft top movement, the controller will automatically retract the roll bar, prior to soft top operation.

Note: Even though the roll-bar may appear to be fully lowered, the controller must see that the S83/5 roll-bar retracted position switch has properly actuated.

There have been a fair number if situations, when the rear bow was not closing and locking properly, even after replacing the S84/16 rear bow lock/unlock assembly, subsequently it was found that the actual culprit was the S83/5 roll-bar retracted position switch, which was discovered using the aforementioned stages of roof I suggested prior, along with and actualization's of the corresponding position/limit switches.

As one example, please read post #'s 207 through 227 here , where MB dealerships using STAR SDS diagnostics, misdiagnosed the real problem and suggested $$$$ in guess work.In another, a forum ,members replaced their leaking (which by inspection were all verified) rear bow lock assembly with a dealer supplied unit, which did not fix their malfunctioning roof.

When MB dealership's used STAR SDS, upon which they did find an issue within the roll-bar assembly, related to the roll-bat retraced switch, but advised that they needed to replace his entire assembly, at $4,000 + labor, because MB no longer provided individual components for the assembly. Ouch!

Others found complete assembles from recycling yards but after cost/shipping and quite a bit of shade tree labor was still expensive.

However, if needed, you can get a new genuine MB S83/5 switch for about $20 (part number provided if needed).

The reason that your 83/5 may not triggering properly varies and is usually not a faulty switch, but due to alignment changes between the roll-bar movement within it's frame.

Note: The fix required in the above suggested post, required additional measures than otherwise needed, which typically have just been a small adjustment in the attachment mounting and/or a shim.
.
Because you did not follow my aforementioned suggestions, at this time, I may/or may not help you more than what I've written above.

However, at this time, all is good.....right?

None the less, let the other forum members know your findings.


,

 

Hi Serndipity,
Thank you so much for yet another helpful reply. Since my last post I have opened and closed the roof about a dozen times, including stopping it halfway through the cycle to examine the broken torsion wires and to figure out how to fix them. Following other posts on this site I’ll be fixing them today.

Since I could not replicate the issue with the roof not opening I cancelled the Star diagnosis with MB saving me $215! However, it was still my intention to do a D-I-Y repair, rather getting MB to “shortcut” my fault finding process .
I would be really appreciative if you could send me the part number for the S83/5. I’ll have a look at that next.

Apart from that all is well here, expecting to come out of lockdown in the next few weeks.
Stay safe, and look after yourself.


Cheers
Pauldy

 

Hi Pauldy,

I reread the entire thread; which essentially said that you have been fault finding your malfunctioning roof since July, thereafter relied on opening and closing your roof manually, until you started this thread in October, when you were no longer able to manually lock the rear bow, because the latch mechanism jammed shut and the rear bow striker was not able to enter into the latch. Fortunately, with the help of a Top Hydraulics video we were able to free up the mechanism.

Thereafter; the first time you tried to open the roof hydraulically, in November, it proceeded in stage 2 where the windows and roll-bar lowered (if previously raised), but failed at stage 3 where the rear bow would not release. I then suspected that the S83/5 roll-bar retracted switch may not have properly actuated in stage 2 and provided additional documents, that wrench handy owners have been able to diagnose, troubleshoot and repair their roofs for short money. Unfortunately, Winter prohibited further progress until now.

Now that Spring has arrived, you're able to hydraulically open and close your power roof and my suggestion would be to enjoy (e.g. you can't fix what's not broken).

However, maintain the access to the power roof components in your boot in the event that it should fail again when opening the roof. If it's at stage 2, you'll be able to check the actuation of the S83/5 roll-bar retract switch in less than 10 minutes, by disconnecting the controller's harness connector, where the pin 16 to vehicle ground should read at or near 0 ohms on a multi-meter. Note: That's pin 16 on the controller, so make sure it's the correct (i.e. corresponding) pin on the disconnected harness connector, which will likely be turned 180 degrees to make the measurement.

The reason that the 83/5 does not actuating properly when the roll-bar lowers, has not been a faulty switch, but caused by the switch no longer making sufficient mechanical contact upon roll-bar movement within it's frame,. As described in the link provided in my prior post, the repair is simply to improve the S83/5 mechanical contact actualization.

Here is an another repair example:

<><><><><><>Included Text<><><><><><>>

Then I checked the resistance between the connector plug and there I found, that the lower roll bar switch gave no signal.

I removed the switch and tested it by hand. And it works. But there are two very thin spacers looking like washers between the switch and the switch threat at the roll bar guiding. I removed one spacer and now it works perfect! It seems that after some time the roll bar guiding may be getting a little loose and does not push the plunger of the switch deep enough. Small problem but big effect.

<><><><><><>End of Text<><><><><><>

Additionally, at this time, I would strongly suggest changing the pump's motor relay, as it switches a highly inductive load (e.g. motor winding) when the contacts close, which stores a high emf voltage, that when the contacts release the resulting spark, in time destroys the relay's switching contacts. A new relay is commonly available and very inexpensive. Here's the cost of the genuine MB OE relay or Hella OEM relay in the U.S..

Lastly, in regard to replacing your tension cables, you might find posts 33 --->38 informative .

 

Hi Pauldy,

Now that a month has passed, fingers crossed, you're been enjoying some top down Spring driving.

What likely happened, since last November and now, was that your roll bar retract switch finally actuated, likely coaxed from driving during courser Winter road conditions.

As more recently discussed, the mechanical contract between the roll bar within it's frame, has at times been an issue pointing to a malfunction of the rear bow not locking correctly, which may have been something you were experiencing for several months, prior to your October post.

Nonetheless, now that you have removed the truck carpeting and the 20 or so firewall plate crews to gain access to the controller, I would continue to keep the access, pending a confirmation, that the controller is correctly being electrically being notified

However, the reason for this note is that of the above.

Specifically, you now mentioned that your next task is to replace your front bow tension cables.

Specifically, if their stretched or broken, when you manically unlatch the front bow, the frame joint above the front windows will not open (see below picture), allowing the hydraulics to continue opening the roof.



When this occurs, upon continued use of the S84 operating which, there is a risk is motor pump motor burnout, which MB corrected in MY 2001 production.

Additionally, are the cables stretched (i.e. unlikely, but can be adjusted)or broken.

At this time, I trust that you have likely watched the Top Hydraulics chapter on how to fix CLk the roof's tension cables.


Specifically, many of the details were omitted.

Unless I was about to sell one of the most reliable examples of MB's having been produced during the last 20 years, sans to power roof operation, I can help you.

The only / best option, is to replace the cables with genuine MB cables, which are still available .

However, getting the end of a new cable, with a swagged on rear button stop, properly installed on the 3rd bow, has has (mysteriously) been problematic for numerous D-I-Yers.

Let me know if I can help further.

 

Hi Serndipity,
only last week I fixed the tension cables. I attached stop end clamps to the ends of the broken cables. I first had to whip the frayed ends with 5 amp fuse wire (see photo) then used plastic tubing to insert and guide the cable through the cross bow holes after first removing the original plastic inserts. The same tubing was then used instead of the inserts because I simply could not re-insert them! The tubing protects the cable from the crop bow metal edges during the roof operation. Originally I tried the repair without removing the roof lining, but my hand and arthritic fingers were not flexible enough!
I took your advice and renewed the hydraulic pump relay.
The fix was partly successful, as on first operation the driver’s side cable failed with the stop end finding its way to the rear seat (second photo). The near side cable was a success and the roof has been operated almost daily since. I’m not too concerned as the driver’s side cable had been disconnected for the 20 years that I’ve had the car! Not sure why it parted as I checked the length against another post that had photos of new cables. However, I did include a washer between the cross bow and the end stop on the driver’s side but not on the near side, so perhaps it had taken up too much slack.
I now need to retension the spring in the trunk screen, which is a 2 man job, so that will happen on Tuesday.
Hopefully that’s me fixed! To be honest I could not have done this without your help and Top Hydraulics excellent pdf procedures.




The following post was also a great help

https://www.benzworld.org/threads/cl...for-1.1546992/

Thanks again!
Pauldy

 

Hi Serndipity,
I bet you thought that was the last you’d hear from me? Sorry to disappoint!
After a couple of weeks of regular deployment of the power roof it has stopped operating! I’m not sure if this is connected but I had been cleaning the inside of the car with the roof down and had moved the drivers seat as far forward as it would go. When I outride to revert to my normal driving position it would not move, not even using the seat memory buttons. The fuses were all OK. However, when I tried to close the roof it failed at 4/5 with the soft top compartment pivoted up hydraulically and the soft top partially out of its compartment. I then closed it manually OK.
The next day I went to investigate the seat position, but first tried to resume the normal seat driving position. To my surprise it worked using the memory buttons.
Anyway, I now need to follow up on switch S83/5 Rollbar Retract switch and as a complete novice I have a couple of questions:
1. Is the test on pin 16 on the controller socket or on pin 16 of the socket on the end of the harness?
2. is the test conducted with one lead of the multimeter on the pin and the other lead to earth or to ground?
3. Should the ignition/ power be switched on or off?
4. Confirm that when doing the test the rear bow, the compartment lid cover are open and the luggage screen rolled up and not extended?

Sorry for all this, but I do value and appreciate your help.
Thank you,
Cheers
Pauldy

 

Hi Pauldy,

I'm beginning to think that your 2001 CLK is possessed.

However, if you continue to experience issues with your power seat operation, start a new thread with further details.

I don't believe having the roof open when you cleaned the inside of the car has any bearing on your issue with not being able to hydraulically CLOSE the roof, which is different then your initial post of not being able to open the roof.

In regard to your 4 questions.

1. Is the test on pin 16 on the controller socket or on pin 16 of the socket on the end of the harness?

The diagram of the 55 pin connector assignments, as shown in post #8, is with the connector mounted onto the controller. As noted in that post, to verify that specific position/limit switches have correctly actuated, you disconnect the wiring harness and make the resistance measurements at the harness connector, being mindful that when looking into the harness (e.g. now likely rotated 180 degrees), that pin 1 on the bulkhead connector will shift from the top left to the top right position, when looking into the disconnected harness connector.

By design, because an extended roll bar could impair specific movements of the soft top, the controller will automatically retract the roll bar, with every soft-top operation. Additionally, at the end of each soft top opening and closing operation, the roll bar is always automatically moved back into the position that it was in before the soft top operation.

My earlier suggestion in post #17, to check the status of the S83/5 roll bar retracted switch, should your top operation fail again, may no longer need attention at the moment, because you were able to successfully open the roof, unless the roll extended thereafter.


2. is the test conducted with one lead of the multimeter on the pin and the other lead to earth or to ground?

Yes and testing the actualization's of all of the other position/limit switches is done the very same way (e.g. switched to vehicle ground). If the multimeter leads are long enough, I would use the negative battery terminal for vehicle ground as well as repeating the test, if a reading does not show a switch actuating, when it should, to insure that the multimeter leads are making a good connection at the connector and vehicle ground point.

3. Should the ignition/ power be switched on or off?

Off

4. Confirm that when doing the test the rear bow, the compartment lid cover are open and the luggage screen rolled up and not extended?

Checking the necessary switch actualization's is always analyzed at the stage where the roof stops hydraulically operating. Do not manually position the rear bow or compartment cover, as doing so may supersede and override the origin of the malfunction.

By design, to prevent a collision between the trunk lid and the lid of the soft-top compartment, while the roof is being opened or closed, the key fob or center console remote trunk release switch will not allow opening the trunk, so you'll have to use the mechanical key to open the trunk.

Because the current malfunction is occurring when closing the roof, below are the appropriate documents showing the key stages involved when opening the roof, as well as the required switch actualization's, that should occur.

Note that the switch statuses are based on the position at the end of each stage, which means that in order for a particular stage to operate, the immediately preceding stage actualization's must also be correct.

BTW, if you review the documents regarding the status of the retractable luggage cover engaged limit switch, it only needs to actuated when opening the roof.

One last thought of interest is that during production of the 2001 CLK, MB incorporated numerous significant upgrades. With respect to the power roof, the controller, pump assembly and compartment cover switch are now entirely different part numbers. For example, the newer pump's valve block eliminated 2 solenoids (e.g. now uses 5 solenoids vs. the former 7) and the compartment cover closed/locked switch eliminated 1 of it's 2 switches and now only checks that cover is locked. The newer switch was used in CLKs produced after May 2001 which also corresponds to VIN ending with 070018 and higher.

Should you have a later production MY 2001, the matrix showing the stages of roof operation vs.the position/limit switch actualization's is still valid (e.g. just ignore checking the A25s1 cover closed switch which is no longer exist). However, the controller still needs to know if the compartment cover is open or closed, which is now done via only the S84/5 switch. Strangely, this switch is not listed in the matrix, as it's installed in both early and later production CLKs. To check whether the controller sees the compartment cover as being opened or closed, measure the ohms resistance between pin 50 and vehicle ground. The cover is completely open at 0-5 ohms and closed at greater than 20K ohms.

 

Serndipity,

Here’s my latest update! I only managed to get to the car this week because of torrential rain for the last couple of weeks!

The last time the roof would not close so I had to close it manually.

When I tried to open the roof this week with the engine running, the windows opened as normal when I released the front bow release handle and raised the soft top, but the soft bow did not open, so Stages 1 and 2 OK but Stage 3 failed.

I continued to open the roof manually.

The Roll Bar headrests were fully retracted.

I accessed the RB Control module N52 and tested each of the pins with a multimeter, against the Soft top opening matrix with the negative terminal grounded on the battery negative, with the following results:

Pin Switch Resistance Ohms

15 S84/11 123 kOhm

34 S83/6 190 kOhm

16 S83/5 180 kOhm

33 S84/13s2 19 Mohm

31 S84/13s1 15 Mohm

50 S84/5 12 Mohm

11 S84/15 down 6 Mohm

13 S84/15 up 63 Mohm

29 S84/16 190 kOhm

28 S69/10 156 kOhm

47 No longer exists

10 A25/s2 12 MOhm

So, from this it seems to me that RB retracted switch (S83/5) is not activated to earth (R =180kohm) yet when trying to open the roof hydraulically, the RB console switch operated normally and flashed for 10-15 seconds then turned off.

I have tried to resync the switches by going through a full manual open and closing roof cycle to no effect.

I have removed the rear seat and can see nothing obvious. I’ve applied force to the RB with the S83/5 switch as suggested in one of the posts (#224) to resync the synchronisation shaft

When I did close the roof manually after all this, the windows did not close via the roof switch and I had to close them on their own switches.

BTW it is a later model with only 5 solenoids as the VIN is higher than the one you posted.

Any hope for this “possessed” CLK?

Cheers

Pauldy

 

Hi Pauldy,

Unfortunately your measurements are not plausible, as it indicates that none of your position/limit are being actuated (e.g. switched to vehicle ground).

As noted in post #22, The diagram of the 55 pin connector assignments, as shown in post #8, is with the connector mounted onto the controller and to verify that specific position/limit switches have correctly actuated, you disconnect the wiring harness and make the resistance measurements at the harness connector, being mindful that when looking into the harness (e.g. now likely rotated 180 degrees), that pin 1 on the bulkhead connector will shift from the top left to the top right position, when looking into the disconnected harness connector.

To insure you're probing the correct pins, before removing the harness connector off the controller, you might mark pin 1 on the harness connector with a small piece of tape (e.g. as a reference point to count from).

Measurements of KOhms (hundreds of thousands) or MOhms (millions) of ohms is off the wall. The expected measurement of an actuated switch will be between 0 and 5 ohms (e.g. which also accounts for some added resistance due to the wiring between the connector and a switch), so when you set your multi-meter to measure ohms, also use the lowest possible ohms range. For example if the lowest range is 100, the meter will accurately only read between 0 to 100 ohms .

As noted in the upper left hand corner of the switching matrix diagram, the limit switch status is based on the position at the end of each stage.

I'm in full agreement with your assessment, that when opening the roof, the failure occurs at stage 3 (e.g. where the rear bow lock should release).

My suggestion would be to again measure the specific switch actualization's required at the point of failure, for correctness as shown in the matrix. Are the S83/5 roll bar retracted and S84/15 rear bow up/down switches set properly?

Note that the prerequisite switch actualization's in stage 2 and 3 are the same and that the status of the rear bow locked limit switch still being actuated is an error in the matrix. It's not, what happens in stage 3 is that the controller sees that the lock is closed and actuates a solenoid on the value block to hydraulically release the lock.

On the matter of which power roof upgraded components have been installed in your MY 2001, the newer switch was used in A208s produced in May 2001 which also corresponds to VIN ending with 070018 and higher and the new pump assembly was deployed in June 2001 (VIN?). The date your CLK was produced will be on a door jam sticker, but since you have access to the pump, just count the number of cylindrical solenoids on top of the pump's valve block.

 

Hi Serndipity,

Thanks yet again for your help. I really do appreciate your time and patience.

I have done as you said and retaken the resistance measurements against the matrix for the soft top opening, identifying pin 1 of the harness connector with a piece of tape as a reference point.

Before I list the results there are some points about the readings. With my multimeter if the range selected is too low and the meter is overloaded at open circuit, 1 is displayed for the overrange condition. When I checked each pin the meter displayed or scrolled through a number of values , for example 3 to 14 M, or 2 to 19 M and then always seemed to stabilise on 1 regardless of the range of measurement selected.

When measuring the resistance for each of the pins I selected the lowest range first and increased the range until I got a reading greater than 1 (the overload/overrange condition)

I also measured the resistance across the ground / earth for the car battery expecting to see something like 0 to 5 ohms. I actually got 185-190 ohms. So, I’m assuming that the meter is not as sensitive or accurate as some others.

Today’s readings are as follows:

Pin Switch Resistance Ohms

15 S84/11 5.7 MOhm

34 S83/6 135 kOhm

16 S83/5 10 kOhm

33 S84/13s2 4.5 kohm but also got 0.9k and 3.8M

31 S84/13s1 16 Mohm

50 S84/5 2 to 14 Mohm

11 S84/15 down 0.9 kohm

13 S84/15 up 2 to 19 Mohm

29 S84/16 2 to 17 MOhm

28 S69/10 11 kOhm

47 No longer exists

10 A25/s2 11 kOhm

From this I assume that the switches for pins 15, 34, 33, 50, 11, 13, are activated in accordance with the matrix.

But I am not sure about the switches for pins 16, 31, 29, 28, and 10.

When I try to open the roof hydraulically the sequence of events is as follows:

1. When the engine is started the RB switch on the console flashes and then goes out. The RB is retracted. When the RB switch is pressed for either extending or retracting the RB clicking of the solenoid switches (??) can be heard. The rear seat and seat back have been removed.

2. Open the manual front bow lock, the windows retract / open and the S84 power switch on the console glows red. When the power switch is operated to open the roof nothng more happens, but can hear switch clicking and then the power switch glows a constant red.

3. Then close the front bow and lock it, the switch goes out ( no red light).

4. Press the S84 switch to close windows nothing happens but hear a clicking and the power switch glows constant red.

5. Closed the windows on their individual switches.

Am I on the right track?
Cheers,
Pauldy

 

Hi Serndipity,

I think I’m making progress! You said in your last post that the ohm readings were not feasible, so I borrowed a friend’s Sinometer M-830B meter, ( You may know it as Mastech M-830B) and I have obtained the following readings (My meter is a Rapitest DM25):

Pin Switch Resistance Ohms Conclusion

15 S84/11 1 or Open Circuit OK

34 S83/6 1 or Open Circuit OK

16 S83/5 00.8 ohms OK

33 S84/13s2 01.3 ohms ??

31 S84/13s1 1 or Open Circuit OK

50 S84/5 1 or Open Circuit OK

11 S84/15 down 01.2 ohms OK

13 S84/15 up 1 or Open Circuit OK

29 S84/16 1 or Open Circuit ??

28 S69/10 00.8 ohms OK

47 No longer exists

10 A25/s2 00.9 Ohm OK



If my understanding is correct then there is a problem with pin 33, soft top open limit switch S84/13s2 and pin 29, Fabric bow locked limit switch S84/16.

The one recurring issue seems to be the Fabric bow lock S84/16 which still becomes locked occasionally when I have to open the roof manually. I then have to release it as shown by Top Hydraulics.



Am I on the right track?



Cheers,

Pauldy