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RM7655L fridge not working on 12v
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userAlanb
Posted: 13 October 2021 10:19 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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


userHymer fan
Posted: 14 October 2021 1:09 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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
userHymer fan
Posted: 14 October 2021 1:39 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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
userbuddy
Posted: 14 October 2021 1:40 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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.

Edited by buddy 2021-10-14 1:51 PM
userHymer fan
Posted: 14 October 2021 3:32 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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
userAlanb
Posted: 14 October 2021 3:53 PM
Subject: RE: RM7655L fridge not working on 12v
 
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With the engine running please.

Alan
userAlanb
Posted: 14 October 2021 8:14 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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
userHymer fan
Posted: 15 October 2021 7:52 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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
userbuddy
Posted: 15 October 2021 8:19 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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) .

Edited by buddy 2021-10-15 8:25 PM
userHymer fan
Posted: 15 October 2021 8:45 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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

Edited by Hymer fan 2021-10-15 9:03 PM
userHymer fan
Posted: 15 October 2021 9:29 PM
Subject: RE: RM7655L fridge not working on 12v
 
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Hi
Can you send more than 100KB on a PM
userHymer fan
Posted: 15 October 2021 9:45 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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
userBrian Kirby
Posted: 16 October 2021 1:19 PM
Subject: RE: RM7655L fridge not working on 12v
 


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Location: East Sussex. Motorhome: Knaus Boxstar 600 Street


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.
userAlanb
Posted: 16 October 2021 2:24 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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
userAlanb
Posted: 16 October 2021 2:36 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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
userHymer fan
Posted: 16 October 2021 2:42 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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
userHymer fan
Posted: 16 October 2021 3:18 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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
userBrian Kirby
Posted: 16 October 2021 4:59 PM
Subject: RE: RM7655L fridge not working on 12v
 


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Location: East Sussex. Motorhome: Knaus Boxstar 600 Street


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.
userHymer fan
Posted: 16 October 2021 5:46 PM
Subject: RE: RM7655L fridge not working on 12v
 
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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
userAlanb
Posted: 17 October 2021 9:49 AM
Subject: RE: RM7655L fridge not working on 12v
 
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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
userBrian Kirby
Posted: 17 October 2021 2:26 PM
Subject: RE: RM7655L fridge not working on 12v
 


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Location: East Sussex. Motorhome: Knaus Boxstar 600 Street


Hymer fan - 2021-10-16 5:46 PM
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

Nowhere close. Nearest would be Lowdham at Huddersfield, next up Travelworld (the Erwin Hymer centre) at Stafford. Depending on where you actually live near Manchester, about 20 miles and 45 miles respectively. I'll leave others to say might would be the best choice, as my only experience of Lowdhams (at their other branch and about 15 years ago), was not that encouraging, and I have no experience whatever of Travelworld.

Have a look here for details: https://tinyurl.com/f8vn3m68
userHymer fan
Posted: 24 October 2021 2:41 PM
Subject: RE: RM7655L fridge not working on 12v
 
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Hi Alan
Just seen your message
Been away
Do you mean take the Block 4 connector out & connect a live wire to pin 1
On the AD01 not the connector
Do I need to run the engine

Thanks Alan
userAlanb
Posted: 24 October 2021 10:38 PM
Subject: RE: RM7655L fridge not working on 12v
 
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Hymer fan - 2021-10-24 2:41 PM

Hi Alan
Just seen your message
Been away
Do you mean take the Block 4 connector out & connect a live wire to pin 1
On the AD01 not the connector
Do I need to run the engine

Thanks Alan

Hi, Hymer Fan,

Likewise, just seen your message, and I am going away for a few days tomorrow

Yes, push a fused 12V into Block4 pin1 of the AD01 to simulate the D+.
It should not be necessary to run the engine, if the connection is only made for a few minutes.
If all else is OK, then the fridge should pull power from the starter battery.

Alan
userJohn25P
Posted: 26 October 2021 10:58 AM
Subject: RE: RM7655L fridge not working on 12v
 
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I found after a lot of effort that the 12v is only available to the fridge when the engine is switched on.

I cannot find a nearby leisure battery connection. Otherwise I would have used the solar system to run the fridge.

J

usercolin
Posted: 26 October 2021 4:10 PM
Subject: RE: RM7655L fridge not working on 12v
 


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John25P - 2021-10-26 10:58 AM

I found after a lot of effort that the 12v is only available to the fridge when the engine is switched on.

I cannot find a nearby leisure battery connection. Otherwise I would have used the solar system to run the fridge.

J

3 way fridges are usually wired so the 12v only works when engine is running, they are not very efficient on 12v so you need a lot of solar for them.
userHymer fan
Posted: 27 October 2021 4:39 PM
Subject: RE: RM7655L fridge not working on 12v
 
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Hi Alan
Just tried the fused wire across to the B4 pin 1 & got the daytime running lights on
I just pushed the fuse wire into the connectors so may not have got a good enough
Connection will have to make a wire with good connections
& try again
So if the DRLs come on it looks like it is the D+signal wire
Unless you know better

Thanks for your help & knowledge
userHymer fan
Posted: 27 October 2021 5:36 PM
Subject: RE: RM7655L fridge not working on 12v
 
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Sorry forgot to mention the fridge
Did not work on the 12v
Hence the bad connection
Will make a good connection wire up & try again

Thanks
userHymer fan
Posted: 5 November 2021 4:36 PM
Subject: RE: RM7655L fridge not working on 12v
 
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Hi
Just a update to where I am up to with the D+signal wire
Been to the storage today took the driver seat out
So I could see what I was doing
Took a wire from the 12v live to the AD01 adapter block 4 pin 1 as Alan suggested
Everything worked as it should
So took a wire from the D+signal wire going into the computer
Behind the interior fuse box
And run it to block 4 pin 1 & everything worked fine
So I think somewhere along the wire it is broken
But trying to find it has been a nightmare
I will solder the wire tomorrow and see how it goes

Thanks to everyone who replied
Could not have done it without your help

Thanks again
userAlanb
Posted: 6 November 2021 3:24 PM
Subject: RE: RM7655L fridge not working on 12v
 
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Thanks for the update. I am pleased that you have resolved your problem.

Alan
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