Hi Everyone,

Firstly thanks for having me.....never been a forum member before so please be gentle with me......should this post be somewhere else? If so apologies!

So.....I have a 2004 CLK 320, 76k on the clock, 2 pervious owners and good MB history. The car was cheap as it had a Gbox issue, but I got lucky as it was just the usual electrical issue with the Gear selector. Mechanically she is lovely, but as an ex London car, she has a few battle scars and i thought too good to scrap.......until now!!!!

Short version of my issue - Roof goes down like it did when it left the factory.......but as soon as you try to raise it, boom "Visit workshop"! Doesn't even try to raise, or start the pump. I now have a good workout every-time I have to close it, but I now have the roof up in under 2 mins with practice!

So the deeper version is, I found a broken switch, the usual on the compartment cover S84/22, so replaced it.......thinking all was well, hood down, no change, still broken. I watched Klaus's Youtube Video lots of times and then changed switch S84/15 - I assumed this must be the cuplrit. Changed for another genuine MB switch.....no different. I then assumed it must be S84/3, so took the whole back seat apart to get to it ( a major faff) - it seems to be fine, so I have not replaced. It was clean and clicked, but i couldn't test it myself sadly.

Lots of messing around later, I managed to get the Control Module Scanned and I have the following codes -

B1923 - Limit Switch Catch Position of the soft top compartment cover, cannot be switched
B1920 - Limit Switch "Open" of the soft top compartment cover cannot be switched

B1903 - Limit switch "Down" of the anti roll bar and RIGHT rear head restraint cannot be switched
B1900 - Limit switch "Down" of the anti roll bar and LEFT rear head restraint cannot be switched

Googling the codes brings up plenty about the SRS system, but doesn't point to a particular issue - worth noting, I do not have a SRS warning light on the dash, which is curious - and it does work!

Not sure if this is related, i suspect it might be, but since owning the car the passenger rear headrest wouldn't stay up when pulled, as if the rachet was missing. No idea how this could be related, but once all the old stored codes were cleared, this started working again and dropped with the dash button as they should.

So took a gamble on ANOTHER switch, purchased S84/13 - compartment cover switch as I assumed this might be the one (as these do fail frequently due to dirt ingress).......you've already guessed it, no change. What i don't yet know is if this has cleared the B1923 and B1900 codes, which is possible I guess.

So can anybody help me please, before I have to sell her for spares. Most garages (even my local specialist) won't look at it, my usual guys are doing me a favour by scanning as they don't want to get involved any further, bless them. I know Cayman Autos are good, but they are an 8.5 hour round trip for me, on a car worth, well, about £500 in its current state!

Sorry for the essay - some other quick facts -
1. I swapped the yellow relays, no change (so both must be ok)
2. Pump works as it goes down ok.
3. No leaks as the level is correct and unchanged
4. Interestingly......if you only open the roof to say 2/3rds open, then close it, it closes fine - so must be switch related, not hydraulic.

I'm sure it can't be much now, i must be close to either fixing it, or losing my mind/temper/dignity probably in that order!

 

Quick Update - so for those that are interested, the Hood is Now Fixed!!

I went back to basic's, testing each switch one at a time (as I had a working spare and the connections are the same on each switch). Weirdly, if you disconnected switch S84/3 (the one buried in the back seat) it would trigger the pump to close the roof. However, when i gingerly attempted to close the roof, the rear cover wasn't actuating properly, resulting in a stuck roof position. So I concluded it must be one of the rear switches and went about testing S84/22 and S84/23 - both found to be working. I just replaced S84/13 the compartment cover switch with a genuine MB new replacement, but tested this via disconnection. This changed the message and stop the boot opening, so from this i deduced the wiring my be intact and the switch operational.

Now i'm at a total loss, all switches appear to operational and the wiring intact as best I could tell and see.

I was just packing away my tools and noticed the top of the windscreen - the only two switches I hadn't messed about with. There has been a nagging in the very back of my mind about these but on the MB wiring diagram, these do not feature in the close procedure until the very end. But something last night said, have a look at them. So I popped off the top cover, undid the 10 screws to reveal the two front switches. First one I activated and deactivated, tried the hood, no change. Second one (above the drivers side), with little hope I activated the switch........BOOOOOOOOOOOMMMMM.....the roof goes up!!!! So a quick clean with carb cleaner and some lithium grease and she's now fully operational!!! - why didn't i just check the switches weeks ago??? Worst thing is, I could have tested that switch without even taking anything apart :-( Also surprised, given the symptom, how it didn't work sporadically (vibrations when driving with the roof down). But there we have it - so a word to the wise, if you have a CLK Cabriolet - clean the switches at the top of the screen once in a while, you won't regret it!

So what have I learned......well i am now a part expert on CLK hoods and the Fault codes were in-fact a Red Herring, as all switches need to be registering the correct signal, regardless of their sequence.

And whilst celebrating the victory of an issue that had bugged me since February, my wife reminded me of the three additional switches I purchased that i didn't actually need as well as the cost of a scan, not to mention the countless hours spent tinkering. I decided not to remind her of the other bits i broke whilst tinkering that i had to replace.......but lets focus on the outcome - I can now say, with a genuine smirk......my roof is now as good as new (i even fixed the rain pocket issues both sides with some new elastic and a needle and thread). Well........until the next issue anyways!

And for those that were interested.......my mind remains intact and most of my dignity......i'll take that as a huge win!