W208 soft top sequence

[chris846]

Hello - this is my first post. It's a request for info; I'm very grateful for the tons of information that I've already found on this forum.

Can anyone please assist with detailed infomration re. the W208 soft top roof sequence i.e. which limit switches & rams operate in what sequence. I would also really appreciate an ident for the 7 solenoids on the hydraulic valve body.

This is to help troubleshoot a misbehaving roof: The sequence (as far as it goes) is as follows:

open manual lever and push up roof
soft top switch illuminates steady
pull soft top switch
all windows drop fully
lock for rear section of roof releases
rear section of roof raises to vertical
lock for compartment cover releases
compartment cover pulls hard shut
motor continues to whine but at higher pitch

The stuff in italics is my guess of where it's going wrong. Tried it today on a diagnostic, but no faults were shown. For the life of me it looks like the pipes to the compartment cover ram have been swapped over (by a real evil person!), but there's no sign that anybody's ever been in there.

Thanks to the forum for all the help so far.

regards
chris

 

[steve333]

Hi& welcome to the forum,i had problems with my w208 clk 320 conv roof when i first bought it( i wasn't pushing the roof up far enough after unlocking it),what problem(s) are you experiencing?

 

[chris846]

hello, thanks for replying
- the problem is where the 'compartment cover pulls hard shut'.
I'm thinking maybe it should be opening instead....

This might point towards the limit switches within the compartment cover lock not working correctly, i.e. not signalling that the lock is released, so's the ram for the compartment lid can proceed and open it.

- but is it normal for the compartment lid to pull down slightly before the lock releases it - can anyone confirm whether this happens or not?

cheers
chris

 

[steve333]

Doesn't sound like it's working properly to me(never noticed mine pull down slightly when shutting)bst bet is to take it to your nearest MB specialist & have it checked over,good luck

 

[tonysurf]

I had something similar, the rear headrests were not fully down. Just a thought might be completely wrong though, good luck. Pls let us know how you get on a problem shared is sometimes a problem halved

 

[chris846]

Yes, I've searched and searched for detailed info: it's my aim (after getting the thing to work of course) to be able to come up with a definitive a-b-c-d-e checklist of the opening sequence & the location & function of all the limit swtches. Seems like there's lots of cases of dealerships saying 'new pump unit' or 'new module' - and hey-ho, it doesn't solve the problem...but costs a fortune!
Headrests is a good pointer, thanks
chris

 

[chris846]

problem identified - a limit switch fixed to the LH ram that raises/lowers the rear roof section. The limit switch is clamped to the body of the ram and buried within the mechanism. It can be reached by removing the interior trim panel. The switch seems to be weak design. It has 2 outputs which sense the rear roof section in the fully lowered postion, and the fully raised postion.
Interesting to note that, owing to it being broken, the switch failed to register the ram fully contracting (which raises the roof rear section). The symptom of this was the compartment cover 'clenching' shut instead of opening as it should - I think this was because the hydraulic pump was still pumping away, but the roof ram was fully extended and so meeting resistance, which raised the hydraulic pressure thus causing the other rams in the system to 'clench'. In the case of the rams for the compartment cover lock and lid, these would still have been set to the closed position, because the control module was awaiting the signal from the broken limit switch.
I only mention this as a conclusion to this thread; hopefully to assist anyone else who might one day encounter the same problem. The other point is that the rams appear to be controlled by 2-position solenoids i.e. whenever the roof is operating, all the rams are pressurised one way or the other. This observation might assist troubleshooting.
regards
chris.

 

[GordyB]

open manual lever and push up roof
soft top switch illuminates steady
pull soft top switch
all windows drop fully
lock for rear section of roof releases
rear section of roof raises to vertical
lock for compartment cover releases
compartment cover pulls hard shut
motor continues to whine but at higher pitch

I have an issue with my 99 w208 cab in that I get to the rear section of roof raises to vertical - mine doesn't raise high enough and the whole thing stops, with the roof switch flashing. Car was off the road for the winter and today is the first time the roof has been tried for 5 months.

Any ideas?

 

[NICKYB]

Does every one elses clunk quite loudly when the rear section of the roof unlocks to rise? slightly quieter when closing the roof however still reasonably loud....

Also what rattles in the roof when driving with it up?> could this be the frame or the plastic rear window surrond?

 

[Lockking]

problem identified - a limit switch fixed to the LH ram that raises/lowers the rear roof section. The limit switch is clamped to the body of the ram and buried within the mechanism. It can be reached by removing the interior trim panel. The switch seems to be weak design. It has 2 outputs which sense the rear roof section in the fully lowered postion, and the fully raised postion.
Interesting to note that, owing to it being broken, the switch failed to register the ram fully contracting (which raises the roof rear section). The symptom of this was the compartment cover 'clenching' shut instead of opening as it should - I think this was because the hydraulic pump was still pumping away, but the roof ram was fully extended and so meeting resistance, which raised the hydraulic pressure thus causing the other rams in the system to 'clench'. In the case of the rams for the compartment cover lock and lid, these would still have been set to the closed position, because the control module was awaiting the signal from the broken limit switch.
I only mention this as a conclusion to this thread; hopefully to assist anyone else who might one day encounter the same problem. The other point is that the rams appear to be controlled by 2-position solenoids i.e. whenever the roof is operating, all the rams are pressurised one way or the other. This observation might assist troubleshooting.
regards
chris.

Thanks for that Chris. I'll add that to my just in case file. Cheers

 

[cpw1958]

I have an issue with my 99 w208 cab in that I get to the rear section of roof raises to vertical - mine doesn't raise high enough and the whole thing stops, with the roof switch flashing. Car was off the road for the winter and today is the first time the roof has been tried for 5 months.

Any ideas?

Hi had the same problem with mine after the snow.Release the valve in the boot (white plastic cup) lower left back seat.Then operate manually a few times.This worked for me,hope it does for you.
Cheers Chris

 

[GordyB]

Release the valve in the boot (white plastic cup) lower left back seat.Then operate manually a few times.

Going to have a look at this at lunchtime, what do you mean by operate manually - move the rear section of the hood up and down by hand or have I got the wrong end of the stick?? What does this valve do?

Thanks

 

[chris846]

Gordy - the valve is a bypass for the hydraulic fluid - when it is open (unscrewed a turn or so) it allows manual operation of the various rams etc.
Chris is suggesting you do this and manually free up the mechanism before having another go.
The flashing switch might mean that you are low on battery power - could make sense if the mechanism is a bit stiff and making things hard work for the pump. I didn't find any limit switch for the rear roof section other than the one on the LH ram (which senses rear section fully up and fully down) - so I don't think your problem (which occurs with the rear section not fully vertical) seems due to a limit switch playing up.
Re. the banging noise when the compartment cover etc. releases - yes, it's horrible isn't it!

 

[chris846]

....the rattle in the roof...
- 'my' rattle was down to the glass window moving against the frame that forms the base of the roof rear section - you can replicate the rattle when stationary by shoving the window a bit. Found that there are 2 rubber studs on the base of the window surround (on the inside) which act as feet - it's these that rub - they are near the bottton corners of the window and you can feel them if you stick your fingers into the gap beneath the window. Stuck some stuff (felt I think!) in there and cured it. Car no longer sounds like an old wreck going over bumps. Probably the only cheap cure I'll ever have with this car!

 

[GordyB]

OK thanks for the info, I'll have a proper go at it tonight if it stays dry.

 

[mercyworky]

Hello everyone this is my first go at this. Does anyone know where all the micro switches are situated that are used by the soft top on CLK W208 as I think one of these might be the problem unless anyone has any other ideas , pictures if possible--- as follows:-

I put the roof down using the switch, it operated and went all the way down then I heard the Bong sound after which the windows and head rest/roll bars went up (OK so far).

I pressed the button to close the roof and windows/head rests went down, then roof closed except -- there was no Bong sound and the windows did not close.

I closed the windows by pressing window buttons - now boot wont open and the roof switch is permanently on and there is a warning Bong as I start to drive off.
Thanks

 

[chris846]

The last limit switch in the sequence is within the lock mechanism that holds the bow (the rear section of the roof) down in place.
As the bow lowers it should lock into place. When this is complete you get the, erm, 'bong'.
Sounds like everything is working on yours, except the limit switch isn't registering the bow fully locked down.
The switch can be accessed with the roof patially opened - use the button to open the roof (which should still work if it is the limit switch at fault) and open it as far as the compartment cover lid fully open, and the bow fully raised vertical.
You can now access the locking mechanism for the bow. The limit switch is just a microswitch fastened to the lock and it is quite possible for the metal tang to bend and so fail to work. It's a simple enough device. You can test its operation by unbolting the locking prong from the bow, and inserting it into the lock to operate it - checking that the microswitch operates.
The other possibility is that the wiring to the limit switch has become damaged at the point where it flexes near the hinge on the driver's side of the compartment cover.
Let us know how you get on - sounds an easy fix once you've sussed it!

 

[chris846]

another one who registered, posted his problem, and hasn't been back since (post #16)
cheeky so and so wanted somebody to dig him out a set of pictures too!

 

[mercyworky]

Thanks very much threadstarter I had a look at the passenger side ram switch that seems OK I will be checking out the switch you sugest and will let you know.
Kindest regards

 

[chris846]

Welcome back!
Not sure if the bow ram limit switch is relevant here - when the bow lowers during the closing operation, it's the bow lock microswitch that senses that the bow is fully down/shut.
The bow ram limit switch (lower limit) only comes into play during the opening operation: when the compartment cover has opened and the bow then lowers back down into the open compartment - the bow ram limit switch (lower limit) then senses that the bow is fully down, and this triggers the main roof rams to open the roof and fold it into the compartment after the bow.
Don't forget to check the wiring to the bow lock - the lock is mounted on the compartment cover, so the wiring to it has to cross the hinge (on the driver's side) - it can get damaged here. This could leave an open circuit so the ECU would never get to know that the bow is locked fully shut - hence the bong.