Technical D+ short curcuit. How to find the 2A fuse? 2021 Ducato

[Kosie5]

I have bought a 2021 ducato camper van and just realised that the leaisure battery is not charged when the engine is running. It is fitted with electro block EBL 119 together with a booster WA 121545. While trying to figure out if the EBL received the d+ signal I found the d+ wire for the booster squizzed underneath the seat baseplate. It has for sure made a short circuit to ground. After fixing the broken cable I still have no signal on the d+ wire at the EBL. I have gone through the fuses in the compartment fuse box with out finding any fuses blown. I can see in some wiring diagrams there should be a 2a fuse just “after” the alternator. Starter battery is charged at 13.8V.

Does any one have any clue where the d+ fuse is located?
Is there any easy way to find out if is 2A d+ fuse is blown or not? ( Engine symbol goes out on the dashboard when the engine is started.)

 

[MSjoberg]

I have bought a 2021 ducato camper van and just realised that the leaisure battery is not charged when the engine is running. It is fitted with electro block EBL 119 together with a booster WA 121545. While trying to figure out if the EBL received the d+ signal I found the d+ wire for the booster squizzed underneath the seat baseplate. It has for sure made a short circuit to ground. After fixing the broken cable I still have no signal on the d+ wire at the EBL. I have gone through the fuses in the compartment fuse box with out finding any fuses blown. I can see in some wiring diagrams there should be a 2a fuse just “after” the alternator. Starter battery is charged at 13.8V.

Does any one have any clue where the d+ fuse is located?
Is there any easy way to find out if is 2A d+ fuse is blown or not? ( Engine symbol goes out on the dashboard when the engine is started.)

This is a guess based on the 2018 model: If the EBL actually was fed with a +12 V signal for D+ (the "raw" signal from the ECU is not +12 V but "active ground") it might come from the Optional Wiring Control Unit (CCO) and Transformer Socket on the right side of the cab, at the bottom of pillar B. You can find info about this in the X290 Electrical circuits doc. under Downloads.

 

[Communicator]

I agree with @MSjoberg that the source may be from the optional connection panel. However as the source is active low, and limited to 300mA, the signal is often routed via a repeater relay module, of which the Schaudt DP02 is an example.

I have attached details of the connection panel. If this is not fitted then the alternator D+ connection to the Body Computer Module (BCM) is at pin 25 of the lower RH connector.

There is a lot of useful information in both the x250 training manual, and the converters and upfitters manual. Both of these are available in the "Downloads" section. See top of page.

 

[Kosie5]

I managed to find a blown 2A fuse. It was place just next to the EBL in between to relays. Under the drivers seat in a
left hand drive vehicle. I have my doubts that this is the D+ fuse I was looking for but now the leisure battery is charging and I also get an alarm when the electrical step I no retracted.

My guess is the fuse and relays are installed by Burstner together with the EBL

I looked in to the “pillar B” connection box and found very little. However one of the wire in the ”pillar B” is a D+ or “ignition on“ signal and also a low amp fuse. ( I only measured with the engine running so I am not sure if it is D+ or ignition). Could be useful information for somebody one day. I will use this signal later for a “auto retraction relay” for the electrical step.

Thanks to Msjoberg and Communicator for their fast suggestions.

 

[HughJampton]

I'd check again which wire is which. The "Converters Manual" for the slightly earlier x290 available as a download on the forum details the connections of the 15-way socket.

Whilst your picture isn't entirely clear, from the position of the connections it would appear that the socket might be "upside down" from the manual description. If so, that would make the red wire "ignition on" (positive with a maximum draw of 600mA) and the green one the D+. This latter is "open circuit" when the engine isn't running, and goes to ground when it is. This requires the converter to add a separate powered source and a fuse and relay (which the going to ground operates) to provide a substantial D+ signal to the EBL. The relay(s) and fuses in your other picture are probably providing this function.

I'm not going to swear I'm correct, as the picture isn't quite clear enough, and a vehicle as late as yours might have a different wiring schema, but the principle is likely to be the same, and if so, it is easy to test the two connections to determine which is which. If things are per the earlier X290 models, and you're getting 12v on the red connection with the engine running, then it's almost certain you've found the ignition-on signal, as the D+ would go to ground under those circumstances.

 

[rayc]

On my EBL 271 the D+ 'Negative when engine running' signal comes direct from the convertors socket i.e. not via a fuse. There is a switch on the EBL to select the D+ output to Haute [high] or Basse [low] to cater for the convertors requirement, which on my French Pilote is Basse [low] i.e. battery negative. The internal Convertor is a solid state chip which also acts as a buffer.
The ebl 119 does not have that facility. I have attached a link to the manual which has a schematic drawing. I am a little puzzled but is it looking for a D+ positive on block 2 / pin 3 with a corresponding positive D+ output on block 1 / pin 2? https://www.aandncaravanservices.co.uk/resources/Schaudt Elektroblock EBL 119.pdf

 

[HughJampton]

Ray,

I think the arrangements are very similar, but with one significant difference.

As above, the switching signal for D+ is conventionally supplied from the "Converters Socket", and Fiat implement this by sending a connection to ground when the engine is running (rather than delivering a +ve 12V signal).

Patently, this ground is of no use as a (12V) D+ signal, so it is generally used to switch an additional relay that has a permanent 12V input, thus effectively inverting the D+ signal and providing 12V with the engine running.

Admittedly, I've only taken a quick look at the EBL271, but it appears the circuitry to do that may be incorporated in the EBL (i.e. it will itself "invert" the signal).

On the EBL119 (and my EBL30) that is not the case. They expect a 12V signal as D+ input, so the "inversion" is carried out external to the EBL. Convertors may use their own system of relays/fuses to do this (and I expect that is the case here) or Schaudt will provide units (such as the AD01 used on my 'van) which will do this (and provide multiple D+ out, and other switched connections).

 

[rayc]

Ray,



Admittedly, I've only taken a quick look at the EBL271, but it appears the circuitry to do that may be incorporated in the EBL (i.e. it will itself "invert" the signal).

Hugh, it is interesting. The EBL 271 is switchable i.e. you can select it to be either high [positive] or low [negative] via the front panel switch. On my Pilote the signal from the convertors socket, which is annotated on Pilote drawings as ' D+ actif bas', goes directly into the EBL. For my systems to work the front panel switch must be set to 'D+ actif bas' i.e. it buffers it but does not invert it.
All external systems e.g. fridge, step retraction at start up etc use the negative D+ to switch them.

 

[HughJampton]

I have to say I disagree

I interpreted the circuit diagram as it containing the appropriate Fiat "inversion" (which must be done externally for the EBL119.)

The switch tells the EBL what "polarity" the incoming D+ signal is. When set to D+ Actif Bas, the EBL expects the switching input to go to ground when the engine is running (if set to the alternative, it expects an input +12V signal).

The extract from the EBL271 manual confirms:

I can only think the facility to switch is provided to support multiple base vehicles (e.g. MB will provide a +ve D+ signal).

 

[rayc]

I have to say I disagree

Hugh, Many thanks of course you are correct. Ray

 

[Soarhead]

Hello all, I came by this forum while trying to solve an issue with my fridge not working on 12v while driving my newly acquired Burstner Motorhome, based on a 2021 Ducato. I’m impressed with the level of knowledge and hope someone can help me expand my own knowledge.

My van is fitted with a Staudt Elektroblock EBL 630 which feeds numerous modules around the van. One of these modules is the Staudt KM630 which controls the fridge. It’s got 12v in but no 12v out to the fridge when the engine is running. I’ve taken the module apart and can see no obvious signs of failure. I wonder if my problem might have to do with the D+ signal? The switch on the front of my Elektroblock EBL 630 is set to D+ active on +12v. I wonder if this is correct or has the previous owner messed with it? Will I cause any damage if I switch this to D+ active on ground to see if this makes any difference? Is there a way to check the D+ signal at the fridge module? All fuses have been checked and are fine. Also the leisure batteries are charging while driving so I know the D+ from the alternator is working. Any advice would be appreciated.

 

[HughJampton]

As per my post not far above, though patently installations may vary so you need to be careful, traditionally Fiat conversions (fitted with the conversion socket) have used a "to ground" signal to represent D+ present,

The ability to switch isn't built into all EBLs - my vehicle with an EBL30 uses an external Schaudt adapter to convert/invert the ground to +12v, which is then fed to the EBL.

My conjecture above was that certain EBL versions had this mechanism inbuilt and could be used in makes other than Fiat by switching..

I'd expect, therefore (but don't quote me) that the EBL should be set to "active low", but if the setting were wrong, I'd expect you to be experiencing issues with charging the leisure battery (though there is a possibility, if you have a B2B installed, that this will bypass any D+ logic in the EBL).

The wiring diagrams are somewhat confusing, but I think it should be possible to detach the feed from block 14 (D+ in/out) and see if there is 12V or ground present with the engine running.

The troubleshooting section implies setting the switch to the alternate value to test shouldn't cause any issues, but again, don't quote me.

 

[Soarhead]

HughJampton,

Thank you for your prompt and informed response to my query. After a little investigation with a multimeter today I discovered that the D+ signal to my EBL is in fact 12 volts positive so my switch at block 14 is set correctly after all. As luck would have it another Burstner Moho pulled in beside me today and the owner kindly let me see his EBL set up. Albeit a different Staudt Elektroblock model it too was set to “D+ active on 12 volts” confirming what I found on my own van. Some clarity perhaps, but I still don’t know why my fridge won’t run on 12 volts while the engine is running! Anyone else got experience of this issue?

 

[HughJampton]

I can only surmise that the inversion of the signal is done externally, but at least you've been able to test.

It doesn't entirely surprise me - my EBL30 relies on an external Schaudt unit (an "AD01") for that inversion, and it also "amplifies" the signal (makes more amps available). The AD01 has other functions however, such as supplying the position lights when the vehicle lights are on. There isn't, as far as I know any such provision internal to the EBL630, so it possibly has a similar external add-on.

Good luck with the 'fridge.

 

[rayc]

Is it a Thetford fridge? When investigating why a friends Burstner's Thetford fridge was not working on 12v operation we found the PCB damaged on the unit fitted to the rear/top of the fridge. It could be accessed via the wall vent The 12v contacts were completely burnt out. I have seen other examples of the same problem on the web and believe it is fairly common

 

[HughJampton]

I suspect the following advice has already been taken, but Schaudt use resettable "Polyswitch" fuses in a number of circumstances. The manual confirms the units are protected by such.

If you haven't already, it might be worth following the reset instructions (I'd probably remove the fridge feed connections from the KM630 first, in case the fridge has tripped something). It's a long shot, but.......

The following functions are protected by a polyswitch fuse:

- All outputs of the bus modules

- Control panel / internal controller in the EBL 630 B

If a fault occurs here, the electroblock must be switched off for approx. 2 minutes and be disconnected from the 230V mains. The polyswitch fuses of the EBL and bus modules reset by themselves during this time.

 

[Soarhead]

Is it a Thetford fridge? When investigating why a friends Burstner's Thetford fridge was not working on 12v operation we found the PCB damaged on the unit fitted to the rear/top of the fridge. It could be accessed via the wall vent The 12v contacts were completely burnt out. I have seen other examples of the same problem on the web and believe it is fairly common

Ray, thanks for your input. It's a Dometic fridge with the PCB strategically located half way between the top and bottom vents and out of reach. It looks like the fridge would need to be removed to access it. In any event, I don't think the fridge is the culprit as 12 volts is not being delivered to the connector block at the base of the fridge. If I found 12 volts at the block, then I would suspect the PCB but I really think the problem is elsewhere. Knowing that and having clarified the polarity of the D+ signal with Hugh's help, I now believe the fault is in the KM630 module. While I couldn't see any obvious evidence of burn marks or blown resisters when I opened it, the fact that this module is receiving 12 volts but not sending 12 volts to the fridge, nor is its red LED flashing like the other modules are, indicates that this is where the problem is.

I've put the moho into storage in Portugal this morning and flown home for Christmas (freezing my nuts off but 'Herindoors' wanted to get organised for Christmas!). I'll revisit this in the New Year when I return to Portugal with printed manuals and wiring diagrams to consult. In the meantime, thank you all for your advice and suggestions. I very much appreciate it and hope that this thread may be of assistance to somebody else in the future.

 

[Soarhead]

I suspect the following advice has already been taken, but Schaudt use resettable "Polyswitch" fuses in a number of circumstances. The manual confirms the units are protected by such.

If you haven't already, it might be worth following the reset instructions (I'd probably remove the fridge feed connections from the KM630 first, in case the fridge has tripped something). It's a long shot, but.......

The following functions are protected by a polyswitch fuse:

- All outputs of the bus modules

- Control panel / internal controller in the EBL 630 B

If a fault occurs here, the electroblock must be switched off for approx. 2 minutes and be disconnected from the 230V mains. The polyswitch fuses of the EBL and bus modules reset by themselves during this time.

Thanks again Hugh, yes I've tried that without success.

 

[KWoods]

Hello all, I came by this forum while trying to solve an issue with my fridge not working on 12v while driving my newly acquired Burstner Motorhome, based on a 2021 Ducato. I’m impressed with the level of knowledge and hope someone can help me expand my own knowledge.

My van is fitted with a Staudt Elektroblock EBL 630 which feeds numerous modules around the van. One of these modules is the Staudt KM630 which controls the fridge. It’s got 12v in but no 12v out to the fridge when the engine is running. I’ve taken the module apart and can see no obvious signs of failure. I wonder if my problem might have to do with the D+ signal? The switch on the front of my Elektroblock EBL 630 is set to D+ active on +12v. I wonder if this is correct or has the previous owner messed with it? Will I cause any damage if I switch this to D+ active on ground to see if this makes any difference? Is there a way to check the D+ signal at the fridge module? All fuses have been checked and are fine. Also the leisure batteries are charging while driving so I know the D+ from the alternator is working. Any advice would be appreciated.

Hi , I have read your post and we have the same issue with our fridge not working on 12volt. We also have an ebl630.
Did you manage to resolve the issue and find a company that provided a KM630 module ? Thanks

 

[KWoods]

Hi , I have read your post and we have the same issue with our fridge not working on 12volt. We also have an ebl630.
Did you manage to resolve the issue and find a company that provided a KM630 module ? Thanks