W124 cabrio roof issues

[Celicasaur]

Hi guys, I fitted a used controller today (124 820 45 26) and sadly my roof issues aren't over. Here's the current position of things:

• The roof is locked at the front part of the tonneau cover, but the rear isn't locked down
• Reset any and all codes via removing negative from battery (assuming that this even does anything)
• Engine running, good healthy charge of battery (I drive the car daily anyway tbh)
• Roof switch is a solid red
• Roll bar switches are showing a solid red
• After I unclasp the front portion of the hood and try to lock the rear of the hood down by pressing the switch forward, I can hear and see a very light amount of movement in the system back there, but it's not locking or unlocking the hood.
• As the main button is pressed, I can see the lights for the roll-bar flashing. When I release the switch, they stop flashing (does this have some significance?)

Please help

 

[Andy_C]

Hi,

Whereabouts are you?

Andy

 

[Celicasaur]

Hi Andy, I'm based at West London - 10 mins from Heathrow...

 

[WDB124066]

Press and hold the rollbar button down for 30 seconds or until you hear a loudish click to reset the roll bar.

Codes won't be reset by disconnecting the battery.

Can you hear the pump running, check the fluid level, use only MB fluid from an MB Dealer.

Check the fuses on the front right suspension turret circled red in the pic, the big strip fuse can blow but it may not be obvious. All available from the Dealer. Do this first.

 

[Celicasaur]

Thank you sir

I've checked those fuses - all appear to be good. I replaced the two white ones last summer anyway to be fair with new items.

Fluid level is good and no leaks - had new main rams (well, rebuilt ones) fitted last summer also. FWIW I went to a garage called Cayman Auto Services in Leatherhead 2 weeks ago and when they plugged their controller in, it worked off the bat.

I just held the roll bar button down for 30 seconds...well...a minute really, but sadly nothing happened.

I did however look under the car and both of the rollbar switches appeared to be in the wrong position like this // so I used my trusty screwdriver to turn them to the correct orientation (according to the manual) which is \\ however...it still hasn't changed anything. Do these need to be replaced for new, or...? Here's their current state:

Driver side

Passenger side

Any other suggestions?

 

[Andy_C]

Hi,
The roll bar switches are marked with the word Function ( Funktien on mine). Your arrow should point towards that. On mine that is the seven oclock position on the drivers side and five oclock on the passengers side.

Have you read the fault codes from the diagnostic port under the passengers front carpet? This is also where you will need to clear any controller errors from.

Why did you change the roof controller? How confident are you that your "new" roof controller works correctly ?

Andy

 

[WDB124066]

If you save it to a file you may be able to read it...

 

[Celicasaur]

Hi,
The roll bar switches are marked with the word Function ( Funktien on mine). Your arrow should point towards that. On mine that is the seven oclock position on the drivers side and five oclock on the passengers side.

Have you read the fault codes from the diagnostic port under the passengers front carpet? This is also where you will need to clear any controller errors from.

Why did you change the roof controller? How confident are you that your "new" roof controller works correctly ?

Andy

Ahh yes indeedy sir, mine is like yours then (it wasn't....but after tweaking it earlier today, it is now) - funny though, I wonder how the roof worked with the shop testing roof controller 2 weeks ago if this roll bar thing was a legacy issue, or if it coincidentally just happened? I followed this handy diagram from the repair manual that I found online via another forum thread:

Loosely related thread URL

No I haven't read the fault codes from under the carpet....can I buy a reader from somewhere, or should I just visit a workshop with a reader? I'm tempted to pop to the workshop tomorrow if they can squeeze me in for a quick one tbh.

Regarding the roof controller...yes....it could well be riddled with it's own problems, this is true. For what it's worth, it's nice 'n' dry and clean inside, which would at least tell me that nothing appears to be cooked from water ingress.

If you save it to a file you may be able to read it...

Many thanks for posting - i'll refer to this if I can get hold of a code reader

 

[WDB124066]

I was once told that the switches should be adjusted so that the tip just makes contact with the plastic spring link covers when the car is on the hoist with both rear axles hanging freely, this from memory. Mine have gone off once mid corner at speed after hitting a severe undulation in the road caused by hot sunbaked tar and trucks plying the seal - so I know it isn't too far off when done this way.
Pic is what they look like when set up like this.

 

[Celicasaur]

Thank you for that.....

Y'know what...I did wonder this while looking at mine. I was thinking....it's not touching anything, so where's the plastic arm going to get the trigger from to know when the car has left the ground....

I'll do some investigating into this and report back.

I also notice that the direction of your sensor thing is like this /
Has the image been flipped horizontally, or is that how it should actually be for the driver side (RHD) car?

 

[Andy_C]

Hi,

The switch is in the same position as the one on mine ( roughly 7 o'clock) on the drivers side.

 

[Celicasaur]

Hmm....i'm confused. If that's the case on yours and on WDB124066....I wonder why the repair manual shows that position as being in the 'arrested' position

 

[WDB124066]

Because I had just had all new suspension fitted and I took the photo before they turned it back to active....

 

[Celicasaur]

Ahhhh gotcha ^ ok fair play buddy, thank you.


I was driving yesterday over a speed bump and heard a loud scary sound....i looked back and the tombstones had shot right up.

I tried holding down the button to get them back down again....no response. My under car sensor arms both appeared to be in the correct orientation, so I'm not sure what exactly tripped off the sensor. if anything, I'd hit speed bumps before with a lot more force than I did yesterday.

I'm going to try and pop into Cayman Auto's again tomorrow to see if they can make sense of this. I wish there were more W124 specialists closer to where I live in West London. I'll update with progress hopefully.

 

[CabrioDave]

"Loud scary sound" - yes, I can imagine that. Interesting that the handbook says that the automatic extension procedure "is accompanied by a clicking sound". Some click!

Have you tried resetting the tombstones exactly as it says in the handbook:
It is possible to retract the roll-over bar in the wake of automatic activation: start by pressing the top of the roll-over bar switch (for at least 8 seconds) until the roll-over bar is heard snapping into place. Then press the lower part of the switch - the roll-over bar is rectracted.

(Although the tombstones aren't really a "bar", that's what the handbook calls them.)

If a "clicking" was loud and scary ... stand by for the "snapping" sound!

 

[WDB124066]

Well what's the difference between a spade and a bar, not much.

Reset them as they say and see what happens...

If you are busy in the driving department the noise of them going off is enough to make them warranted - if not more, and that's dangerous in my book!

FWIW you're not a real Cabbie owner until you've had them go off mid-corner - just be ready for it!

 

[Danyal29]

I’m also having issues with my w124 cabrio roof, the when I unlatch the 2 clips from inside to open the roof, the roof button goes red and when I pull , nothing happens. I checked all fuses and they are fine, so is the fluid . Also battery health is fine . When I use the rear headrests / roll bar, it goes up and down perfectly . I did come across one thing , which are the little control units connected somehow to the roof , and this is how it looks , could this be the cause of roof not working. They are both facing 7 o clock, from what I have heard , one is meant to be in 7 o clock position and the other one in 5 o clock position, could this be the issue, how could this off happened by itself if I used the car not too long ago. I had used it 3 weeks ago and was working fine , and was parked up that whole time, when I came around to drive it again, and attempted the roof, would not move. Please help