Mercedes based central locking problem

Just had my Auto-Sleeper Bourton at the Mercedes dealers to correct a fault on the central locking ie. the passenger door and habitation door will not lock or unlock via central locking, after spending considerable time and fitting a new door lock it transpires that it is not a Mercedes issue but a fault with the way A/S wired the habitation locking to which at the moment they do not have a cure, there are quite a number of vehicles affected which I believe are the 2013/2014 models, mine worked from new for around 7 weeks then packed up, while I was at the garage another Merc arrived with the same problem, I am sure Auto-Sleepers are working on a fix but if yours packs up it could be due to the same problem and not a warranty issue with Mercedes, the Mercedes workshop by the way were great and very helpful and always have been with my previous Mercs.
Don

Is this your first problem Don?

yes, everything else has been fine, nothing broke or fell off and all worked as it should, my previous 2 Mercedes based models the locking worked fine  so I believe this only affects the ones with the "new style" body, I am perfectly happy with the van other than this small hitch which though inconvenient is not so big a problem and I am sure A/S will soon find a fix.
Don

Just experienced the exact same issue on our new Mercedes Malvern (6 weeks old!!) during our recent 3 week trip to Ireland. Mercedes in Dublin performed a diagnostic test and confirmed that it was a Mercedes unit failure - part replaced and all is well so far. We will have to wait and see!!!

Yes Liam the part that has failed is a Mercedes unit but the way it has been explained to me is that the part has failed due to the way auto sleepers have wired the habitation door unlocking into the passenger door unit causing a short to earth that has ruined a unit which will have to be replaced, Mercedes say that as it is due to auto sleepers wiring that this has occurred they are not liable under warranty and auto sleepers seem to agree with this so it seems you were fortunate in getting the Dublin dealer to replace under warranty, hope that the new unit is not shorted out.
Don

Thanks Don,This is indeed worrying! What, if anything, is AS doing about a fix - have AS accepted liability on your behalf? Maybe I was lucky but the dealer in question did say that this unit did often fail on the Sprinter van itself (which I assume why there was one readily available in store on the day. Also, as all of my vans details had to be entered into the Merc data base before authorizing the replacement which suggests that they were happy to accept liability despite knowing that it had been converted and presumably the AS electrical designs signed off by Merc.
Liam

Hi Liam, yes my Merc dealer has spoken to auto sleepers and was told there were quite a few vehicles that have had this problem and they are close to getting a fix, they are going to send the parts to my garage for them to fit when available so it seems that auto sleepers have accepted responsibility for the failure, I was told that they would be writing to myself and the other owner that arrived with the same fault to explain what is happening, my previous 2 sprinters were perfect I can only assume that is on the new ones. I believe they also have plans to fix the other vehicles affected.
Don

Hi Don, Interesting, sounds like I should be talking to AS to include me on that list to ensure I am covered if it occurs again. Whilst it was a painless fix (particularly to the wallet!!) it nonetheless did take up best part of a day of my holiday running around and sorting it all out. Also, I was concerned from a security viewpoint been away from home, as both of the doors in question would not be alarmed and therefore vulnerable to a break in and leading to all sorts of issues from an insurance standpoint! Liam

I'd be very interested to find out how this central locking works if anyone can help?

Prior to this thread starting I had been researching the subject as a matter of interest. What I have found suggests that the lock actuators are electric motors operated by short pulses of power, the polarity being changed to reverse the action.

There is a master lock that initiates an action. That operates two changeover relays in a manner that flips the polarity back to the actuator in the master lock. The other actuators are slaved on a 2 wire circuit from the master.

From reading above I'm guessing that this circuitry has change in the new Mercedes models and that the AS addition is applying a permanent feed to the slave Mercedes lock causing the motor in the actuator to burn out.

Again this is complete guess work so I'll be delighted the hear from someone who actually know.

Peter

Hi Peter, I am afraid I cannot really help you with that level of detail other than to say that there are 2 modules servicing either side of the vehicle and it is the one on the near side (passenger) that failed in my case causing the remote locking mechanism of both doors (cab and habitation) on that side to be none operable. 

I believe there is a general outstanding connectivity issue between the Auto Sleeper habitation door mechanism and the Mercedes vehicle. In that the vehicle central locking system does not recognize the  habitation door as a legitimate means of entry when unlocking, thus requiring you to open a cab door to prevent it rearming whilst you are inside or indeed locking you out! As you may be aware it rearms in 40 seconds if the vehicle cab door is not opened. 

The Mercedes dealer did have the vehicle on a diagnostic machine during the whole process and I would have thought they would have seen any such anomaly as you describe with the system during that time. 

It might be that the module circuitry is only capable of servicing one door and any excess power could on occasions cause it to fail. 

As I understand it, in my case it was a hardware failure rather than an actuator failure.  
Liam

Hi guys, I'm a new user of this website. I'm Barry, the other A/S Merc owner Don refers to above. Mine is a Winchcombe.

When I saw Don's vehicle already in the garage workshop being worked on I wondered whether this may be a common fault and queeried the garage to check whether it was a Merc problem, or an A/S one.

From what we were told at the Merc garage, A/S spliced into the wiring in the passenger door to pick up a feed for the habitation door. It seems the increased power load to the passenger door wiring has short circuited (blown up) a SAM unit, a Merc electronics module costing £300 - £400 (£ouch). 

As Don says, we were told A/S were contacted and agree it is their faulty wiring that has caused the problem. Whether Merc originally accepted A/S intentions to modify their wiring I cannot say. But it seems A/S are working on a "fix" rewiring loom and will send the parts to the Merc garage to fit to our vehicles as soon as they have proven to be suitable (when that will be, we don't know) I hope it's soon though. Also A/S will have to pay for replacement SAM units for the 18 vehicles so far known about. Interesting that Liam says above that the SAM unit is known to fail!!

Barry.

So why don't A/S simply splice in via a relay for the hab door solenoid. That won't solve the re-arming problem but a relay should solve the excessive current issue that blows up the SAM unit when two solenoids are connected!
I am pleased that the Peugeot does not seem to have either of these problems.
The only related issue that I have is that you only get one remote key with a new Peugeot and the Cobra alarm fob will only open the front doors. Also that fob does not flash the indicators when locking and unlocking - probably because the Cobra norm is One Flash for Unlock and two for Lock while the Peugeot standard is the other way round - more logical as you count the syllables in Lock and unlock!

I can't think why A/S didn't use whatever wiring Mercedes use (when Merc build a vehicle having a sliding side door that presumably locks at the same time as the 2 cab doors?) to energise the locking mechanism on their habitation door. Perhaps that wiring doesn't exist on chassis cabs.

Equally, I can't say why A/S didn't do any of the things asked about in this thread. I can only say what was said to both Don and myself by the Merc garage site manager, Bryn, after he had contacted both Auto-Sleepers and my dealer, West Country Motorhomes.

Regards, Barry.

Same problem occurred on my Stanton in week six from new. Pleased that I had Thule cab and habitation locks fitted from new otherwise would have been concerned leaving the unit on site. I also have an aerial problem that requires the vehicle going back to AS but I will wait until they have a fix for the locking problem.

Plato.

plato2012 wrote:I also have an aerial problem that requires the vehicle going back to AS.

Plato.

I'm curious - what are the symptoms of the aerial problem?

Peter

Peter Brown wrote:

plato2012 wrote:I also have an aerial problem that requires the vehicle going back to AS.

Plato.

I'm curious - what are the symptoms of the aerial problem?

Peter

FM searches for stations but usually only finds Radio 1 and a local station, if I tune manually when stationary, I can get radio 4 but it soon breaks up once moving. Just had a call from AS, booked in for next Tuesday to correct along with the fuel level sensor in the LPG tank which shows empty when the are still 12 litres in the tank.
I have queried the central locking situation which appears to affect all new Mercedes and apparently they will disconnect a sensor when I visit, then the vehicle goes to Mercedes for a replacement, then the dealer can correct the fault.
Hopefully all my troubles will be over.
Regards Plato

Thanks. It just sounds like a bad connection when they re-installed the aerial.

Peter

With regard to the LPG level I think you will find many on this forum have the same problem. The gauges fitted to our vans are no more than a very base guide to what gas you have in the tank. I doubt that AS will be unable to rectify the situation, what do others think?

Claytaa wrote:With regard to the LPG level I think you will find many on this forum have the same problem. The gauges fitted to our vans are no more than a very base guide to what gas you have in the tank. I doubt that AS will be unable to rectify the situation, what do others think?

AS believe that the problem is the sensor/float in the tank and plan to remove the tank and fit a replacement checking accuracy as they fill it. Hopefully something more accurate after they have finished.
Regards
Plato

Claytaa wrote:With regard to the LPG level I think you will find many on this forum have the same problem. The gauges fitted to our vans are no more than a very base guide to what gas you have in the tank. I doubt that AS will be unable to rectify the situation, what do others think?

AS believe that the problem is the sensor/float in the tank and plan to remove the tank and fit a replacement checking accuracy as they fill it. Hopefully something more accurate after they have finished.
Regards
Plato

That's us told! (Lol)

Sorry gents, I didn't wish to cause offence. I believe the gas tank problem is an excellent issue to discuss, but not on this thread perhaps? It could raise more awareness of the problem amongst members as a seperate thread, that's all.

AS are probably correct in their belief that it's the float arm/sensor setting. The float controls the level to which the tank is filled before it stops more gas coming into the tank (just like the float in a toilet cistern) If that's a problem it might need bending slightly? The sensor sends an electrical signal to the indicator (on the dash) what level to indicate. The reading is only a guide, there's no precision in the reading. I have seen a gas tank not fitted accurately in it's radially vertical axis (upright) giving strange problems too. I'm certain AS know what they're doing, they'll sort this out.

As for the reading on my 'vans gas tank indicator, I'll get the 'feel' of it with experience in time. When the guage reads empty, I'll fill the tank up, note the amount of gas filled and gauge this against the tank manufacturer's capacity rating given on the form supplied with the 'van when it was supplied to me (25 litres).

'Nuff said by me, I'll shut up now. Sorry for my 'gassing on', when I've already complained about it.

I wondered what was going on with this thread - having been away for a few days and left it talking about MERCEDES BASED CENTRAL LOCKING PROBLEM - I find its dissolved into a discussion on gas - I agree with stoneb's sentiments. 
For those that are really interested in the original thread - I am visiting A/S Willersey service center tomorrow when hopefully a solution will be forthcoming and I will appraise you on my return of the outcome.
liam

plato2012 wrote:Same problem occurred on my Stanton in week six from new. Pleased that I had Thule cab and habitation locks fitted from new otherwise would have been concerned leaving the unit on site. I also have an aerial problem that requires the vehicle going back to AS but I will wait until they have a fix for the locking problem.

Plato.

Plato,
Did you have the Thule locks fitted at manufacture or by the supplying dealer? Also I would be interested to know which type you went for, as we have a 2015 Stanton on order for October(?) delivery.


Thread drift: the main reason for sticking to topic is to allow the search function to operate to the best of its (sometimes limited) ability. For example, if I needed to know about the accuracy of the gas-tank gauge and put those words in to "search" none of the important stuff which has been discussed above would be found. Even if a search by content (rather than thread title) was run, assuming this thread was found, I would be unlikely to open a thread titled as a central locking problem!

Cheers,
Pete.