Sink tap problem

[DPS20K]

I’ve got an interesting problem with the sink tap in my 2021 MP. The first half a dozen or so times you use it the tap works just fine, but then the next time it doesn’t work and there is no pump sound. The pump hasn’t been running long on any occasion so hasn’t overheated. I checked the fuse and it was fine, and on reinstalling the fuse the tap worked again, for the first few times! Now the really interesting bit is that I then noticed that when the tap isn’t working, the main light in the accommodation area also doesn’t work - you can’t switch it on manually with the switch. I then turned the light on using the phone app and the light worked, and the tap started working again. I now use this trick every time it happens and it always works. I am guessing there is a problem with the MBAC control unit but was just wondering whether anybody else has experienced a similar issue.

 

[Grand Tourismo]

I’ve got an interesting problem with the sink tap in my 2021 MP. The first half a dozen or so times you use it the tap works just fine, but then the next time it doesn’t work and there is no pump sound. The pump hasn’t been running long on any occasion so hasn’t overheated. I checked the fuse and it was fine, and on reinstalling the fuse the tap worked again, for the first few times! Now the really interesting bit is that I then noticed that when the tap isn’t working, the main light in the accommodation area also doesn’t work - you can’t switch it on manually with the switch. I then turned the light on using the phone app and the light worked, and the tap started working again. I now use this trick every time it happens and it always works. I am guessing there is a problem with the MBAC control unit but was just wondering whether anybody else has experienced a similar issue.

My MP isn't new enough to have the MBAC but this is the first time I have read of the app being able to turn on the tap remotely! I would like to see a video of that...sorry I can't help but it does sound software related.

 

[The fat controller]

This is absolutely bonkers!

I did have the tap not work on one occasion but only one so far. Haven't used the sink much though so I'll keep an eye out for this.

 

[Epigram]

Worth letting MB know, Either a wiring fault or the guys writing the software for the MBAC app got their wires crossed. Worth mentioning to MB anyway in case there is a mod.
Its a pity a wiring diagram isn’t easily available

 

[Steve B]

I'm a big fan of the technology in cars, and miss not having carplay etc. But it's getting to the point where everything is controlled by a phone or smart control unit. Fixing issues is just going to get more complicated as we go on.

 

[Epigram]

I agree. The Internet of Things is great In many respects. I find it useful to know what the electric lawnmower is up to when I’m on holiday and have the doorbell ring me ”to tell tales” when it has escaped.
However, with a camper that may have a life of over 20 years, I am not so sure. How many versions of programming languages will there have been during that time making the system obsolescent. It’s bad enough keeping the GPS map data updated !
There is a lot to be said for keeping things simple.
I also wonder how well software is tested. Regression testing is expensive and, if it is not safety critical, and achieves appoximate functionality, it is probably more economic to put into the field for customers to find faults.

 

[Carol]

l also just had a tap problem whilst touring France , worked fine at lunch time this evening nothing . I have found a blown 10 amp fuse , so will see if l can get one in the next few days

 

[Roofie]

Hi all,
My Mp I’ve had for 3 years all good with sink till now and not really major use! I’m with a mechanic now and covering options, it’s not 10am the fuse he has discovered a known sensor switch below the actual tap that plays up! Looking into now but think I’ll be sending back to Mb,
Also on other investigations found out that in winter to take the 10am fuse out in case of burnout which makes no sense to me thought I’d mention
I’ll let you all know if and how I get sorted

 

[Roofie]

Oh since found out when bought from new the fuse is in the glove box in a plastic bag maybe our previous findings are correct remove fuse when not needed or it will burn the pump out
I’ll keep all posted

 

[Epigram]

Several threads on here about taking the fuse out to stop the pump running and burning out with no water in the tank. A bit of a fiddle so I use a stout rubber band (heavy duty wrist band) around the tap to keep it firmly off when the tank is empty.

 

[Simon and Elie]

I’ve got an interesting problem with the sink tap in my 2021 MP. The first half a dozen or so times you use it the tap works just fine, but then the next time it doesn’t work and there is no pump sound. The pump hasn’t been running long on any occasion so hasn’t overheated. I checked the fuse and it was fine, and on reinstalling the fuse the tap worked again, for the first few times! Now the really interesting bit is that I then noticed that when the tap isn’t working, the main light in the accommodation area also doesn’t work - you can’t switch it on manually with the switch. I then turned the light on using the phone app and the light worked, and the tap started working again. I now use this trick every time it happens and it always works. I am guessing there is a problem with the MBAC control unit but was just wondering whether anybody else has experienced a similar issue.

Yes I have this exact problem on my 22. The MBUX just doesn’t work well enough. I have the whole MBUX system just turn off sometimes and turning the key is the only way to turn it back on. I’ve had probably a dozen different problems and am about to say to customer service to give me a vehicle that works. The latest problem is the leisure battery won’t charge from the mains.

 

[DogWagen]

Kitchen tap failure has happened a couple of times to me - I turned on the shower switch, pump ran and then the kitchen tap worked. MBUX is OK but still does hiccup every now and then.

 

[Epigram]

Yes I have this exact problem on my 22. The MBUX just doesn’t work well enough. I have the whole MBUX system just turn off sometimes and turning the key is the only way to turn it back on. I’ve had probably a dozen different problems and am about to say to customer service to give me a vehicle that works. The latest problem is the leisure battery won’t charge from the mains.

If you are minded to reject the vehicle do it quick! You will get fobbed off and MB will keep on stonewalling with excuses until it’s out of warranty.Their fault finding capability with software faults is hopeless.
The voice instructions on my Command satnav have bever worked properly from new In 2019.
Investigated multiple times by MB and formal complaints to Customer Service as well as the Motor Ombudsman MB stonewalled until out of warranty and then were not interested and told ”It’s not their problem becuse it’s their software supplier and out of their control “
The Command fault persists and I eventually gave up and had Apple Carplay installed and use that instead.