Rear passenger door lock stopped responding to fob or internal button

[john2006]

Hi guys.

I noticed today that my rear drivers side door lock has stopped responding to the key fob or the internal button. I can open the door from inside using the handle but otherwise it will never lock or unlock.

I tried pushing the little stick? (button?) to lock the door manually this DOES work and locks the vehicle so that is the only way at the moment to secure the vehicle. However, I noticed that when I press this little stick/button on the other doors, there is a smoothness to it and a little "notch" just as you begin pushing it down. On the door that doesn't lock, there feels like a lot of resistence and it resists the entire way down. It almost feels like I'm trying to turn the steering wheel without power steering, it's just "hard". It does engage the lock however.

Any thoughts as to what could be wrong? I google searched quickly and some suggested it was electrical but would need a error code reader to check but I don't have one of those yet. Will probably get one on amazon for tomorrow but in the mean time, any ideas?

Thanks guys

 

[AMGeed]

Had the same problem with my 2009 C180. It needed a new door actuator.
Cost approx £200 + fitting. Not a job for a DIYer either as you need a special size Torx bit to remove the actuator that is only available to main dealers and Mercedes specialists.
If the actuator fails when the door is locked, you won't be able to open it either from outside or inside. Then its an MOT fail.
Get it looked at before it fails completely.

The Part number for a passenger side rear is A204 730 43 35

 

[john2006]

Hi there thanks for responding, very useful information. I came to the conclusion that it must be the actuator (from what I have been seeing online) and having seen some videos of this job on youtube, I decided I will not be attempting this myself. So I very much agree with you that this is one for the mechanics. Good to see a rough idea of cost, I've sent a few requests for quotes out to a few local garages so I'm not sure what they're going to quote me (if they will even take on the job - for some reason these days mechanics don't seem to want to take on jobs? or play it off to another garage who also wont take it on...?) but yeah I'll see what they say.

I just spent £150 sorting out an oil leak.

 

[AMGeed]

Hi there thanks for responding, very useful information. I came to the conclusion that it must be the actuator (from what I have been seeing online) and having seen some videos of this job on youtube, I decided I will not be attempting this myself. So I very much agree with you that this is one for the mechanics. Good to see a rough idea of cost, I've sent a few requests for quotes out to a few local garages so I'm not sure what they're going to quote me (if they will even take on the job - for some reason these days mechanics don't seem to want to take on jobs? or play it off to another garage who also wont take it on...?) but yeah I'll see what they say.

I just spent £150 sorting out an oil leak.

I hope the garages giving you a quote are aware of the requirement of a special size tool to remove the actuator.
Also, don't be tempted by a cheap eBay actuator. Chances are the electrical connector will be different. Ask me how I found that out!
If the garage knows what they are taking on, I'd imagine somewhere in the region of 2 - 3 hrs labour for the job.
If you have one, I'd use a Mercedes specialist. May be a little more expensive labour wise, but he should b familiar with the job.

Edit. I notice you mention the drivers side (offside) rear door. Don't order the same Part# I quoted. That is for the near side rear door.
Get the part from the main dealer or leave it to the specialist.

 

[john2006]

Hi there, yeah I did manage to get the right part number in the end but I decided to leave it for the specialist to obtain and sort out. So far, I have only had 1 quote... so I'm waiting for some more. The only person that has agreed to do it so far is a mobile mechanic and he has quoted £120 all in. Seems a little cheap from what I've been reading and of course what you posted. Still waiting the other quotes, i think tomomorrow morning I'm gonna start ringing around seeing what that yields.

 

[EmilysDad]

...... as you need a special size Torx bit to remove the actuator that is only available to main dealers and Mercedes specialists.
.....

I'd be surprised if MB & specialists had the sole rights to a specific Torx bit. You say, elsewhere on the Web, that they're a 5 point bit rather than the usual 6 point ..... loads of 5 point Torx on eBay

It didn't take the aftermarket long to supply the 12 point bit for Ford's Pinto head bolts way back in the day

 

[AMGeed]

I'd be surprised if MB & specialists had the sole rights to a specific Torx bit. You say, elsewhere on the Web, that they're a 5 point bit rather than the usual 6 point ..... loads of 5 point Torx on eBay

It didn't take the aftermarket long to supply the 12 point bit for Ford's Pinto head bolts way back in the day

Neither 5 point or 6 point torx bits fit the offending bolt. It's a MB only tool I understand.
My mechanic has a mate in the main dealer at Poole and managed to "borrow" the tool for the cost of a drink.

 

[EmilysDad]

Neither 5 point or 6 point torx bits fit the offending bolt. It's a MB only tool I understand.
My mechanic has a mate in the main dealer at Poole and managed to "borrow" the tool for the cost of a drink.

I'm even more curious now

 

[Snake Charmer]

WIS shows these special tools, the right three are for rivet removal.

 

[john2006]

Ohh right so the special tools are the tools to remove the rivets? yeah the tutorials just tell you to drill those out and put new ones in so I guess this would make sense as to the special tool part then. This is also 50% of the reason i'm reluctant to do this job myself lol

 

[Snake Charmer]

I looked at a couple of the YouTube tutorials, they showed a long Torx T20 is needed to slacken off the lock retaining screw that stays captive in the door.
The special rivet removal cutting tools are designed to take just the heads off, presumably to stop heavy handed Technicians under the cosh of a dealer dictatorship bludgeoning through the door tinwork with an oversize blunt drill bit whizzing round flat out in their new Snap-On cordless drill and smashing the window.

 

[john2006]

So I'm actually in the process of doing this job myself. I got stuck... at literally the part you've mentioned @Snake Charmer . I had a 20t screw driver and I put it in the hole but whilst going pretty much the entire driver length in, there was nothing that seemed remotely like a screw. Since then and now seeing your post, I realize yeah the problem was that the screw driver is not enough. So I've ordered and it now arrived, a much much longer one....so tomorrow, I will go for round2. I'm super nervous about what Im going to find when I pull this out... but honestly... I'm just hoping for the day this is over now. lol

 

[Snake Charmer]

I bought a set of long Wera Torx drivers specifically for removing the door mirrors on my S211, really long shafts on them as a 1/4" drive bit will not go in there easily.
Take your time, working inside door panels is not easy, quite often you cannot see what you are working on.

 

[john2006]

Hi so bit of an update! the job is now complete but there's a side issue that I have to resolve. So, the problem I got stuck on before was that seemingly my original torx screw drivers were either not long enough... or I was using the wrong size by mistake, like maybe a 27 or 30 either way I was hitting air most of the time... or nothing that felt like a screw. Having got the extra long 250mm length t20 torx it took less than a minute to locate the screw and this is what was preventing the panel and the acutator from actually coming out of the door. There's a very tiny plastic sliding clip that slides between the door handle's cradle? and the top of the actuator. Lord knows why they clipped it together... maybe some stability for the actuator because it just flops around almost otherwise. Anyway, the sad part is, I assume from my constant yanking on it the other day, that when I tried to reassemble everything that little clip broke at the softest of touches... but either way nothing serious really. Everything is now back in the door and the lock now fuly works, remotely included.

The side problem I was mentioning is that for some reason now, the window on that door stopped going up and down properly. If I make it go up with auto up, it will not work or auto down will not work. and when I make it go up manually it gets to the top then drops about 1-2inchs everytime and then I have to press up again a few times before it will stay up.

I googled and followed reset guides (about 10 times) I can only geet the auto down to work. The auto up and the manual up still won't work as expected. It made me wonder if maybe the glass is not fully "down" inside the door frame but I checked and it seemed to be fully down to me. Surely if it wasn't fully inside the bracket that holes the glass and pushes it up/down then when it goes down it would surely still stick up a bit? at least that's my thoughts. Otherwise, I have no clue why it wont reset but either way, it's a minor problem. Never use this window anyway.

 

[Snake Charmer]

Good news, pleased to hear you managed to replace the lock. To reset the windows on my S211 I usually hold the window button up and down until I hear a relay click on each door.