Alanb Posted October 7, 2021 Share Posted October 7, 2021 Hymer fan - 2021-10-03 10:19 PM Hi buddy At the starter battery there is a 50amp fuse & a 2amp fuse the 2 amp fuse is connected to the Starter battery have tried to trace this cable but from the battery it goes under the rubber matting & cannot trace without taking the seat out and the rubber floor up There is no 20amp fuse near to the battery cannot find this Hymer Fan, Sorry I missed your mention of the 50A fuse when I was scanning through the thread earlier today. The presence of the 50A fuse at the starter battery suggests that your vehicle may not have a converters panel. When you get access to the EBL, may I suggest that you start your tests by checking both starter battery and habitation battery power are present at the main terminals at the rear of the EBL, by testing between terminals. The middle terminal (2) is shown as being connected to habitation battery -ve, so presence of starter battery power here would suggest that the connection between both battery negatives is present, but also worth a physical check. Alan Link to comment Share on other sites More sharing options...
Alanb Posted October 8, 2021 Share Posted October 8, 2021 Hymer Fan, Missing D+ and 20A Fridge Fuse I cannot see that you have confirmed/refuted that the base vehicle is in fact a Fiat Ducato. I will therefore assume that it is an x250 Fiat Ducato. On this vehicle the D+ signal originates at the alternator as a yellow wire with a red stripe (Ye/Rd). There is a colour change to Bn/Gn at the "front engine connector" under the engine bay fusebox. The Bn/Gn wire terminates at pin A25 of the body computer. The body computer is directly coupled with the cab fusebox. If a connection has been tapped into the basic D+ signal, it should logically be adjacent to the body computer. The alternative D+ signal is from the converters panel as suggested by Keith, but the signal there is active low (connected to earth when engine running), and would need a relay module (relay in a box) to convert to active high (+12V) before connecting to the EBL. The non visible 20A fuse makes me wonder whether your fridge has been connected as suggested previously by "buddy". I could speculate further, but I think that your findings as to the location of wires on the EBL should come first. Alan Link to comment Share on other sites More sharing options...
Hymer fan Posted October 8, 2021 Author Share Posted October 8, 2021 Hi Thanks Alan not had chance to check everything yet Will have to read your post a few times to get my head round it all Will get back with my findings Thanks again Link to comment Share on other sites More sharing options...
Hymer fan Posted October 13, 2021 Author Share Posted October 13, 2021 Hi Just a update have still not been able to find where they have spliced in to get a D+signal To the electroblock 101 Have checked the wire from the alternator all the way through to the body computer & have power up to that point Is it possible to splice into this wire and take it to the electroblock Or does it go through the computer If not Would I need another relay before the electroblock Also I have a AD01 box under the driver seat (no D+signal here either) So the daytime running lights will not work Is there a relay on the cab fuse box that has something to do with the D+signal wire Thanks Link to comment Share on other sites More sharing options...
buddy Posted October 13, 2021 Share Posted October 13, 2021 There are relays in the ADO1 adapter and D+ seems to be linked to it , if you google Schaudt ADO1 it brings up a PDF of a instruction manual at aandcaravanservices .resources. This includes the wiring in to / inside / and out of this unit showing D+ connections etc. Sorry but do not know how to do a link , Link to comment Share on other sites More sharing options...
Alanb Posted October 13, 2021 Share Posted October 13, 2021 From the info provided by buddy, it seems probable that the D+ signal is repeated via the AD01 relay module. If this is the case then D+ should be connected to AD01 B4/1, but in order to provide outputs at Block 5, it will require starter battery +ve & -ve at B1/1 & B1/2 respectively. However I understand from your latest post that you have checked round the AD01, for D+ signal. Is it possible to trace the D+ connection back from the AD01 B4/1 ??? In answer to your question, I would not expect to find a D+ associated relay on the Fiat wiring. Your fridge did work, so you are looking for either a blown fuse, or a failed connection. Have you managed to find where the fridge 12V element is connected to on the EBL, possibly at Block 1? Alan Link to comment Share on other sites More sharing options...
Hymer fan Posted October 14, 2021 Author Share Posted October 14, 2021 Hi buddy Yes I have looked at that and downloaded on to my tablet The B5 connection is where the D+signal should be (But not there) if I put my Multimeter on it I get numbers just jumping about on the screen I have found the D+signal wire all the way up to the computer behind the cab fuses But where it goes from there I don't know Thanks for your time buddy Link to comment Share on other sites More sharing options...
Hymer fan Posted October 14, 2021 Author Share Posted October 14, 2021 Hi alan Not been able to find where the 12 element wire is on the EBL Tried to trace the D +signal wire back from the AD01 But goes into the harness under the dash Traced the D+signal wire from the alternator To the body computer & is live (engine running) Do you think it would do any harm to the electronics If I link a wire from the D+signal wire To the AD01 to see what happens Thanks for your help Link to comment Share on other sites More sharing options...
buddy Posted October 14, 2021 Share Posted October 14, 2021 I think that B5 is the exit side of the AD01 for the D+ and as Alanb has said the D+ entry into the AD01 is at B4 pin 1, possibly from the ECU , if it is there (engine running) but not at B5 I think that may indicate a faulty AD01 As stated above , you need also to confirm that starter battery power is getting to B1 for the AD01 for it to operate its relays as it should. Link to comment Share on other sites More sharing options...
Hymer fan Posted October 14, 2021 Author Share Posted October 14, 2021 Hi buddy I can confirm that there is 12v power at B1 Will have to check B4 Control voltages vehicle To see if there is any power there Thanks again Link to comment Share on other sites More sharing options...
Alanb Posted October 14, 2021 Share Posted October 14, 2021 With the engine running please. Alan Link to comment Share on other sites More sharing options...
Alanb Posted October 14, 2021 Share Posted October 14, 2021 Hymer fan - 2021-10-14 1:39 PM Hi alan =============================================================================== =============================================================================== Do you think it would do any harm to the electronics If I link a wire from the D+signal wire To the AD01 to see what happens Thanks for your help I am not fully conversant with the Fiat x250 alternator control circuitry. It is different to that on my x244, as the D+ signal connects to the BCM, which the x244 does not have. The copies of diagrams for the x250, that I have access to have lost definition in the copying process, and do not allow close inspection of the alternator internals. It is not clear as to whether the BCM on the x250, monitors the alternator output, or provides the regulator function as well. I believe that the latter possibility is the most probable, and as the maximum field current of a vehicle alternator is typically about 3A, the BCM should be able to supply the extra load. That being said, before making a new connection, I would try to find out where and how the connection is usually made, before adding a new one. You say that the D+ wire to the AD01 module disappears into a harness under the dash. Is this a Fiat harness, or a Hymer addition? Is it possible that a tap connection has been hidden under the harness tape? Alan Link to comment Share on other sites More sharing options...
Hymer fan Posted October 15, 2021 Author Share Posted October 15, 2021 Hi Alan I have just received some wiring diagrams from hymer It looks like the 2amp fuse at the starter battery should be a 20amp fuse And it looks like the D+signal wire does come from the AD01 adapter I will try to send a photo of the wiring Thanks again Link to comment Share on other sites More sharing options...
buddy Posted October 15, 2021 Share Posted October 15, 2021 Hymer fan, there should be a wiring diagram of the AD01 printed circuit board showing the D+ into and out of the AD01 along with its internal circuits etc on page 10 of the manual that you have downloaded (if it is the same as mine) . Link to comment Share on other sites More sharing options...
Hymer fan Posted October 15, 2021 Author Share Posted October 15, 2021 Hi buddy Still trying to download the diagram Looks like it won't let me download it It is a pdf file there are 5 diagrams & it is 1.96kb in size Will not reduce it I will keep trying Thanks Link to comment Share on other sites More sharing options...
Hymer fan Posted October 15, 2021 Author Share Posted October 15, 2021 Hi Can you send more than 100KB on a PM Link to comment Share on other sites More sharing options...
Hymer fan Posted October 15, 2021 Author Share Posted October 15, 2021 Hi Alan On the AD01 on B5 there are 2 yellow wires one that I have Traced under the dash It looks like it goes into the harness which looks like the fiat harness Which without undoing all the tape under the dash I cannot find where it goes The other wire is slightly thicker (yellow) seems to go under the floor But heading towards the electroblock Will have to do a bit more delving Am away till Tuesday (not in the van) So will have to wait until I get back Thanks for your help Link to comment Share on other sites More sharing options...
Brian Kirby Posted October 16, 2021 Share Posted October 16, 2021 This seems to have become worryingly complex. At the outset the problem was an AES fridge that had suddenly ceased functioning on 12V. In very simple terms, either the electrical system had lost it's D+ signal, the relay/s operated by the D+ signal had failed, a critical wire had become damaged/disconnected, or the heating element on the fridge had failed. We now seem to be deep into trying to re-wire parts of the fridge circuit without really knowing the location, or nature, of the original fault. This seems to me to raise the danger that such re-wiring might unintentionally create conflict with the original, presumed still live, circuits, or create unintended malfunctions elsewhere. Might it not be preferable to step back for a moment and work down the circuits again, step by step, testing at each location, to identify what has actually failed, and where? For example, aren't the switching relays housed within the Elektroblock? Couldn't they be tested by attaching 12V supplies to the relevant terminals. Couldn't end to end continuity of the relevant circuits be tested by using extended multimeter probes (albeit that may require two pair of hands)? I'm not trying to be clever clogs, but just have a nagging suspicion - which I can't justify technically - that excessive intervention when lacking precise knowledge may not solve the primary problem while causing another. It did work, so surely it should work without needing part re-wiring? With apologies to all. :-) Link to comment Share on other sites More sharing options...
Alanb Posted October 16, 2021 Share Posted October 16, 2021 Alanb - 2021-10-14 8:14 PM =============================================================================== It is not clear as to whether the BCM on the x250, monitors the alternator output, or provides the regulator function as well. I believe that the latter possibility is the most probable, and as the maximum field current of a vehicle alternator is typically about 3A, the BCM should be able to supply the extra load. =============================================================================== Alan Since making this post, I have carried out some research, and discovered a copy of the Fiat x250 Training Manual. It is alengthy document with a large quantity of usefull information. I have managed to extract the following pertinent clause. "Signal Alternator The NBC measures the level of voltage on the D+ circuit and compares it with the battery voltage. In the event of trouble with the alternator, the fault is signalled with the specific symbol lighting up. This measurement is only made with the key on." May I therefore correct my previous suggestion. On the x250 the BCM (NBC) only monitors the alternator output. Alan Link to comment Share on other sites More sharing options...
Alanb Posted October 16, 2021 Share Posted October 16, 2021 Brian, You are echoing my own thoughts. Which are find out what has gone wrong, and make a repair, rather than add a workaround, which may as you rightly suggest cause further problems in the future. I quote below, what I said, and I see that I have repeated myself. Probably due to rephrasing "That being said, before making a new connection, I would try to find out where and how the connection is usually made, before adding a new one." Alan Link to comment Share on other sites More sharing options...
Hymer fan Posted October 16, 2021 Author Share Posted October 16, 2021 Hi Brian Yes it does seem to have gotten over complicated Everything was pointing towards the electroblock Sent that away come back as no problem found Everything now points towards no D+signal But trying to trace wires is a bit of a nightmare I got some wiring diagrams from hymer in germany Which shows a 20amp fuse where somebody has put a 2amp fuse Only had the van 12month but not been able to use it for about 9month Due to the Covid So is still pretty new to me Maybe somebody before me had a problem with it And changed a few things So without the relevant information just guessing Thanks Brian Link to comment Share on other sites More sharing options...
Hymer fan Posted October 16, 2021 Author Share Posted October 16, 2021 Hi Alan As I am running out of ideas and steam on this one You are right I am not a electrician So maybe time to hand it over to a auto electrician Maybe he will find the problem straight away Too many electronics on them today for the DIYer Thanks again for helping All that contributed Link to comment Share on other sites More sharing options...
Brian Kirby Posted October 16, 2021 Share Posted October 16, 2021 It seems part of the problem is that it is unclear whether the fault lies in the fridge, the Hymer installations, the Fiat installations, or their various interfaces. Rather than an auto electrician, it therefore seems to me that you really need the services of someone who knows how Hymers are built and wired, which would point me to a Hymer dealer, ideally one with Fiat trained technicians who can carry out vehicle servicing in their workshop. You haven't said what part of the country you live in. It it may help if you do so, as someone is likely to know which of the dealers nearer to you are reliably likely to have the right mix of technicians to quickly identify and fix the fault. Having said that, you may find the workshops are quite heavily booked into next year, so getting the fault fixed in the immediate future may not be feasible. Of those offering servicing (though the exact scope of the offer isn't clear in all cases without contacting them), Travelworld seem to have the widest offer and the best equipped workshops. Failing them, Southdowns seem a possible alternative, but enquiries may reveal more conveniently located others. Link to comment Share on other sites More sharing options...
Hymer fan Posted October 16, 2021 Author Share Posted October 16, 2021 Hi Brian Yes I think I need a Hymer technician I live nr Manchester so anybody know of anyone local Do you have an address or telephone number Thanks Link to comment Share on other sites More sharing options...
Alanb Posted October 17, 2021 Share Posted October 17, 2021 I am sorry that you have not resolved your problem. However before engaging the services of an auto electrician, you may wish to conclusivly prove the fault to a missing D+ connection, as is suspected. This could be done by unplugging the AD01 Block 4, and connecting pin 1 of the AD01 to +12V. To gaurd against a possible fault in the AD01, this test connection should be made via a low rated fuse, or a 12V test lamp. If every thing works with the connection in place, you will be able to direct assistance to the specific area of the fault. My apologies if you have already done this previously, and I have not noticed it while when scanning the thread. Alan Link to comment Share on other sites More sharing options...
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