Dethleffs electrics

[Keep Right On]

8 month old Dethleffs Trend, 1400 miles. On way to day out in New Forest. Internet not working - checked router = low battery. Odd its hard wired in installed pre-delivery. Thinking fuse at this stage.
Then realise water pump not working, loo doesnt flush, cabin lights don't work and fridge isn't on, so returned home.
My technical knowledge says electrical fault.

Leisure battery is fine 12.9 but main engine battery only 12.2 despite having driven 80 miles. Checked fuses - 40a, 20a, 2 x 12a all fine. Googled local dethleffs repairers. Premier at Chichester - " no they only do work on vans they've sold - have to take it to selling dealer" (Travelworld at Stafford). How without main battery charging and no facilities?
Had rung Travelworld "sorry tech staff on phone - we'll get them to ring you straight away - 1 hour 20 mins later missed call but voicemail to check fuses and call back if no joy. Did so, no reply.......

Reliance also Chichester were excellent though - some first aid advice and promise to get it in next week for a diagnostic check - may need to get dethleffs approval before carrying out work.

Any thoughts on cause? Its on ehu at home when not being used so surely battery can't be naff on a new van?
Ta!

 

[stubroo]

My 2018 Trend has a master cut off switch on the control panel, it turns off the 12 volt supply to most things. On mine it is just a small button situated between the two battery test buttons on the control panel.

 

[ED O'DARAC]

Hi, I am assuming that you have a good engine battery, but that your leisure battery is not powering the rear (your voltages suggest the opposite). Stubroo is correct that there is a master switch for rear 12v cunningly concealed on the EBL blue box under the passenger seat (not on the control panel above the fridge or above your door).
However, have you tried hooking up on mains to see if the rear equipment works when on mains? If it does, the fault is probably a fuse that will also be cunningly concealed which connects the leisure battery to the engine battery/alternator charging. On my last van this had blown and mine presented your faults but, if hooked up, everything worked again.

Alternative explanation: The latest vans have a 'clever' smart alternator designed to help with meeting Euro 6 emissions standards. They charge in a very different way to good old fashioned ones. (Much less).
This can present problems when you drive as your AES fridge switches to electric and many people report that this can cause a serious drop in leisure battery voltage until the system can rebalance.
However, your system voltage does sound extreme, so the battery or a fuse could have gone AWOL.
Reliance Chichester are great and will help you out. However, TravelWorld are very good as well.

 

[stubroo]

I took a picture of the control panel on mine. The master switch is the one below the illuminated symbol on the left. Usually positioned conveniently so you can turn it on or off.
I'm sure you would have noticed it before if you had one positioned there though.

 

[Keep Right On]

I took a picture of the control panel on mine. The master switch is the one below the illuminated symbol on the left. Usually positioned conveniently so you can turn it on or off.
I'm sure you would have noticed it before if you had one positioned there though.

Yes, thats the same as mine. It occurred to me in the early hours that maybe I had turned it off accidentally and I looked out through the window to see if there were any lights or anything left on which could be draining but the only thing I could see was the control panel illuminated.
I haven't deliberately touched the CP and it wasn't mentioned on the handover video. Everything just worked from Day 1, but having checked everything back home on ehu, nothing was working, with the low engine battery level noticeable. It has charged up on ehu but nothing doing.
Will check later as it;s had a good 18-hour charge now.

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[stubroo]

Try pushing the master switch a few times, you should hear the click of the electromagnetic relay. If you can't hear anything then the problem must be further back between the habitation battery and the control panel.

 

[Bustup15]

I have a different model but experienced similar problems. The main fuse between engine and leisure batteries had blown, on mine located adjacent to the engine battery under cab floor. It was a 70A fuse.

When blown caused the fridge to run from the leisure battery when the engine was running and flattened it pretty quickly.

German dealer later upgraded this to 80A as it happened on other occasions.

 

[autorouter]

If it's a nearly-new van, don't assume anything at all. Get a multimeter and check for yourself the battery voltages at the actual terminals. Is it the leisure battery that's 12.9V and the starter battery that's 12.2V? Or is it the other way round?

What make/model is the distribution/fusebox and the control panel?

 

[Keep Right On]

Update: Someone with a fat finger had pressed the off button on the control panel........
All working now and both batteries holding their charge. Just been out to check and off EHU I have 13 on leisure and 12.7 on starter.
Thanks for all of the help - will take it for a little ride tomorrow to make sure all charging while driving

 

[stubroo]

Glad your sorted

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[Keep Right On]

Update: Someone with a fat finger had pressed the off button on the control panel........
All working now and both batteries holding their charge. Just been out to check and off EHU I have 13 on leisure and 12.7 on starter.
Thanks for all of the help - will take it for a little ride tomorrow to make sure all charging while driving

Update - modern Fiats have a "smart alternator" apparently so they only create as much charge is needed at any one time as opposed to fully charging it. Thats why it seems to only have a low charge even after a decent run. Thats according to Adams Morey in Portsmouth who were, by far, the best garage I have experienced in a long long time!

 

[Lenny HB]

Update - modern Fiats have a "smart alternator" apparently so they only create as much charge is needed at any one time as opposed to fully charging it. Thats why it seems to only have a low charge even after a decent run. Thats according to Adams Morey in Portsmouth who were, by far, the best garage I have experienced in a long long time!

Should have a B2B fitted to overcome the smart alternator problems.

 

[Keep Right On]

Ignorance here - whats a B2B?

 

[Lenny HB]

Ignorance here - whats a B2B?

Battery to Battery charger, you fit it between the starter battery and the leisure battery. Enables the leisure battery to receive a higher rate of charge it fools the smart alternator to keep working when it would normally shut down when it considers the starter battery charged.

 

[Keep Right On]

Update #2
Does anyone know whether new Dethleffs ( ours is a 2021 trend 6757DBM ) has a battery to battery charger fitted as standard? Originally thought I had van battery charging issues but fiat dealer assured me all was good and after seeing replies to this thread was going to arrange a B2B to be fitted
However, yesterday did a 400-mile round trip with no mishap other than the engine fan switching on for few minutes after we parked (probably just aircon but not been aware of it before).
This morning having done 2 miles, the EMS light came on and message on dash to stay stop start not available and to check engine. Van battery level seemed OK and message disappeared but EMS light stayed on. Drove 40 miles on motorway but first stop at a junction and stop/start definitely not working still. Parked up and van battery had 12.2 which I was told is ok because of smart alternator.
Decided to return home just in case but stop/start still stopped and EMS light still on.
Will contact fiat tomorrow but any thoughts? I guess b2b might help but if it takes power from van to leisure battery, won't that will make matters worse in drawing power from the van battery?
Ta

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[Lenny HB]

I would expect your van to have a B2B as standard perhaps it has one and it's faulty.
A B2B would help the situation as it would keep the alternator working therefore putting more charge into the starter battery as well as the leisure battery.

If the starter battery is only getting to 12.2v I would be very worried that is only 50% charged, probably too low for the stop-start to work and in danger of damage to the airbag ECU.

 

[Keep Right On]

I would expect your van to have a B2B as standard perhaps it has one and it's faulty.
A B2B would help the situation as it would keep the alternator working therefore putting more charge into the starter battery as well as the leisure battery.

If the starter battery is only getting to 12.2v I would be very worried that is only 50% charged, probably too low for the stop-start to work and in danger of damage to the airbag ECU.

Thanks Lenny - first call to van dealer tomorrow and then to Fiat who put the van battery on diagnostics 2 weeks and said all was normal.........

 

[autorouter]

I guess b2b might help but if it takes power from van to leisure battery, won't that will make matters worse in drawing power from the van battery?

A B2B doesn't take power from the starter battery, even though 'B2B' sounds like that's what it's doing. It only switches on when the engine is running, and takes power from the alternator in the same way that headlights, wipers and fan take power from the alternator. When the leisure battery is full, the B2B dials back to float charging, which takes a minimal amount of power from the alternator. While the B2B is working, the alternator is at a higher voltage than its 'idle' mode, so the alternator will be charging the starter battery more than if there was no B2B.

 

[Keep Right On]

Thanks Lenny - first call to van dealer tomorrow and then to Fiat who put the van battery on diagnostics 2 weeks and said all was normal.........

Latest update having spoken to Dealer and Fiat garage:

1. There's definitely a fault
2. They don't know what it is
3. Fiat said it could be a flat battery from standing in the dealers yard. Dealer says, no way
4. It could be a gas sensor or something to do with the cat converter - bit random that one
5. Dealer says there isnt a full B2B but what he calls a buck boost - one way starter to the leisure battery but not the return trip
6. They will link up with diagnostics next week - the fact the EMS light is on means there is a code in ther. which will tell them what the fault is. They may talk to Fiat Italy to agree the fix


Laters.......

 

[Lenny HB]

Dealer says there isnt a full B2B but what he calls a buck boost - one way starter to the leisure battery but not the return trip

That is a B2B, typical dealer not got a clue.

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[Keep Right On]

That is a B2B, typical dealer not got a clue.

I thought a full B2B was 2 way - starter to leisure and back again?

 

[Plumb]

I thought a full B2B was 2 way - starter to leisure and back again?

I wonder can’t you ask the breakdown recovery that comes with Fiat to have a look they will carry out a diagnostic check . I did that with mine my vehicle went into limp mode and also lost stop/start it turned out low battery voltage because I had moved the vehicle several times in short succession. Have not had a problem since.

 

[autorouter]

I thought a full B2B was 2 way - starter to leisure and back again?

A B2B is the name for a battery charger that is powered by another battery or a DC source like an alternator. Most B2Bs charge the leisure batteries from the alternator/starter battery. There is a method to ensure the B2B only works while the engine is running, either a high input voltage or a feed from the alternator D+ (engine running) signal.

A few B2Bs have an extra function, where (if the engine is not running) the leisure battery trickle-charges the starter battery if the leisure battery is being charged. By solar or EHU charger for example. But most don't have this function.

 

[Reallyretired]

Update - modern Fiats have a "smart alternator" apparently so they only create as much charge is needed at any one time as opposed to fully charging it. Thats why it seems to only have a low charge even after a decent run. Thats according to Adams Morey in Portsmouth who were, by far, the best garage I have experienced in a long long time!

Seems that 'smart' is a euphanism for something that doesnt work properly so smart alternators that dont charge batteries and smart motorways that cause accidents.
Nobody has ever described me as smart which is a blessing.

 

[Keep Right On]

Seems that 'smart' is a euphanism for something that doesnt work properly so smart alternators that dont charge batteries and smart motorways that cause accidents.
Nobody has ever described me as smart which is a blessing.

I was once described as smart arse..... keeping fingers crossed

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[Keep Right On]

Update on electrics/battery - went into Adams Morey this morning and they have diagnosed needs a new Particulate Matter Sensor and battery is in fact ok. The fault on the sensor causes the start/stop function to disable itself and this in turn pushes the EMS light on. Problem is that the new sensor is on back order and could be weeks/months - they already have 4 on back order and really don't know when it will be in.
Found a thread on Fun from last year which suggested it was a known problem on new Fiats and that a recall programme had started in 2020-21 to replace it. Have asked dealer to confirm whether mine was done prior to collection as new last October
Question: is it safe to drive in the meantime?
Question 2: Does anyone know where I can get hold of a PMS?

particulate matter sensor = PMS (my van has PMS!)

 

[Plumb]

Update on electrics/battery - went into Adams Morey this morning and they have diagnosed needs a new Particulate Matter Sensor and battery is in fact ok. The fault on the sensor causes the start/stop function to disable itself and this in turn pushes the EMS light on. Problem is that the new sensor is on back order and could be weeks/months - they already have 4 on back order and really don't know when it will be in.
Found a thread on Fun from last year which suggested it was a known problem on new Fiats and that a recall programme had started in 2020-21 to replace it. Have asked dealer to confirm whether mine was done prior to collection as new last October
Question: is it safe to drive in the meantime?
Question 2: Does anyone know where I can get hold of a PMS?

particulate matter sensor = PMS (my van has PMS!)

Yes could be worse could have had an ASBO

 

[jezport]

Update on electrics/battery - went into Adams Morey this morning and they have diagnosed needs a new Particulate Matter Sensor and battery is in fact ok. The fault on the sensor causes the start/stop function to disable itself and this in turn pushes the EMS light on. Problem is that the new sensor is on back order and could be weeks/months - they already have 4 on back order and really don't know when it will be in.
Found a thread on Fun from last year which suggested it was a known problem on new Fiats and that a recall programme had started in 2020-21 to replace it. Have asked dealer to confirm whether mine was done prior to collection as new last October
Question: is it safe to drive in the meantime?
Question 2: Does anyone know where I can get hold of a PMS?

particulate matter sensor = PMS (my van has PMS!)

Call fiat camper assist. They will get it to your dealer in days. Had a friend with the same issue.

 

[Keep Right On]

Call fiat camper assist. They will get it to your dealer in days. Had a friend with the same issue.

Rang Travelworld straight after getting the call from Adams Morey to see if they had any of the sensors and if they knew about any product recall. When I asked to be put through to a technician I was told that she couldn't do that as they were short staffed. Recommended I went on the website instead and sent a message which the Service Manager would see and contact me. No reply in 6 hrs......
If I can find a sensor anywhere, I will get it but lots of people on the Dethleffs FB page have the same problem it seems. If Adams Morey have 4 (5 including mine) on back order, it does not bode well for a quick fix.......

 

[Nedge68]

This does seem a common problem, and is normally fixed with a new sensor. The new cleaner diesels do need to be allowed to regenerate the DPF, if the engine is just run for short journeys the engine doesn’t run through a complete cycle, and just clogs up.
This happened to a car I owned, ended up with a DPF light on, cured it by taking it for a long drive, and keeping the revs up.

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