Electrical nonsense from S211

[corned]

Hi all.

Before I go and get the car plugged into Star, I wondered if anyone out there had any advice on what to look at in this case?

I have had a couple of what appeared to be random events which I now think are related.

The car alarm went off a few nights ago, but no problems were found. I wondered about the old spider walking across the occupancy sensor trick and thought nothing more of it.

Then the car alarm went off again the day after and I could see the car from my office window. Again, no obvious reasons for the alarm.

On Saturday, we were travelling up the M1 when I became aware of the rear dome light being on. I immediately chastised the kids for playing with the switch, which I soon found out they hadn't done. I switched the rear dome lamp off using the switch on the front dome lamp. It went out, but kept coming on every few minutes after that. I then used the other switch which seems to knock out all dome lighting - front and rear. Problem 'solved'. Until the cluster lit up bright red with a 'tailgate open' warning. It wasn't. Then a few miles later, the rear load cover (which was deployed) took it on itself to run up its runners and block my rearward view. WTF?

Last night coming back home, the rear dome light started its tricks again, and I switched it off again from the front switch. The 'tailgate open' message came back, and to top it all off I could then hear an intermittent clicking noise from all around the car. I pressed my ear to the driver's door and could hear the clocking coming from inside. Everyone reported similar from their own doors. I can only assume this was the central locking messing about, although it didn't actually unlock any of the doors. I pressed the central locking button on the centre dash and the doors opened. No further clicking was heard.

What the heck is going on? And where do I start looking? It's been very wet - have I got water in something I shouldn't?

All the problems now look very much related - security/entry/exit related.

The car has had no issues overnight.

Any help would be very gratefully received.

 

[Peter DLM]

Seems to me that the little switch/sensor that senses when the tailgate is open is either loose, or malfunctioning in some way. I don't know where it is, but it'll be somewhere around the frame of the tailgate, probably along the bottom under the silver trim.

I had a similar issue, but mine was the bonnet sensor.

It may just need cleaning/tightening/hitting.

 

[shorty]

It will be the tail gate lock . This is where the switch is located that detects wether the door is open / shut .

 

[corned]

Thanks, Peter and Shorty.

I think it is going to be something relatively daft like that. Not that I am saying your suggestion is daft, you understand! I'll see if I can get that trim up and see what's going on under it...

 

[shorty]

Theres no switch under the crome trim a the rear door opening on a s211 . All thats under there is a door catch , the switch is part of the door lock

 

[ringway]

Hi Keith,

Classic symptoms of water or moisture in the pse control unit I think.
I can't turn up the thread just now but have a look at my Alarm and anti towing sensor misbdhaving thread from August I think.

On my W210 the control unit is under the rear seat next to the battery. It is housed in a foam boot.

See also my control unit threads.

Cheers,

Paul.

 

[corned]

Thanks, shorty - I did actually wonder if that's what you meant. Thanks for the clarification!

Paul - your thread on water ingress was foremost in my mind. I will be very unhappy of that is the root cause.

Time for a bit if digging methinks!

 

[shorty]

Theres no pse pump in the 211 , the locks are worked by motors . There is a control unit in the rear door , its on the drivers side , this is connected to the lock and then to the rear SAM via CAN bus . The rear SAM also works the interior lights and rear load cover . This could also be where the fault lies .

 

[corned]

Thanks again, shorty. Can you tell me where the rear SAM is, please?

 

[Diesel Benz]

Does water on the trunk floor reach the rear SAM?
Êàòàëîã

 

[corned]

Thanks, DB.

That area is dry as a bone. I have also had the rear-facing seats out and checked under the floor. The spare wheel well and battery area are also bone dry.

As a few viewers may recall, I had the tailgate treated for rust (under warranty) earlier in the summer, so I am hoping that it does not relate to a legacy from that repair. I'll get the tailgate interior trim off tomorrow and have a good look inside...

 

[shorty]

It could be worth checking that the plug into the door lock is located correctly ,and free from moisture . It would seem IMHO that the door lock is faulty .

 

[jaymanek]

yep seconded for the boot latch.. it just thinks its open hence the blind going up and lights coming on.

 

[corned]

Haven't yet plucked up the courage to tackle this job!

However, today looks like being my lucky day in this respect.

Please will someone advise on what I need to remove/undo to see what's going on?

Do I need to remove all the panelwork, or can I see what is needed by simply undoing the interior handle?

Finally, can someone tell me what the little switch-looking thing is/does in the door latch? Top left of the latch part as you look up to the bottom of the tailgate from underneath.

 

[jaymanek]

im pretty sure you will need to remove all the trimmings on the inside of the boot lid to get to the lock.

 

[shorty]

Finally, can someone tell me what the little switch-looking thing is/does in the door latch? Top left of the latch part as you look up to the bottom of the tailgate from underneath
This is for the child lock , disables the inner door release .

To acess the lock the whole carpet covered panel and the coloured plastic panal has to come off . These are held on with push in clips , than the carpet panel will slide up and off . The upper light coloured window frame cover migh need to be released at the bottom to allow the carpet covered panel to slide up enugh to release from the door

 

[corned]

Brilliant, Jay and shorty!

Many thanks for your continuing help. I'll have a go over the weekend as I didn't get chance to start today after all. Mind you, it has behaved itself impeccably in the last few days, so hopefully only a minor connection problem. We'll see!!!

Thanks for the child lock ident. I could not find reference to it in the manual. I did check - honest! The manual only refers to the sliding lock on the inside handle.

 

[glontis]

Hi, I have the same problem, seems to occurr after heavy rain (2005 e280cdi estate) Indy has changed a few things, but problem remains - did you ever get yours fixed? Help!

 

[corned]

Hi there.

The problem has sort of gone away. I.e. the tailgate electrical nonsense itself has stopped. However the root cause of the problem is not yet sorted to my satisfaction. See here for details.

I am deliberately staying away from that thread for now - keeping my powder dry, if not my spare wheel well...

 

[glontis]

My problems started after paintwork on tailgate. I checked forums, there is a MB bulletin re leaking rear wiper grommet, I think mine was disturbed during painting when the wiper arm was removed. The garage has confirmed water getting into tailgate in this area, there is corrosion in some of wiring and this has caused false alarms, luggage cover problems etc as the door open sensor is triggered incorrectly by water after heavy sustained rain (normal weather?) Door sensor, motorised door lock, alarm/lighting module replaced all unnecesarily. MB make an uprated wiper grommet apparently, fingers crossed!