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CI Riviera 181 (Fiat Ducato 2.8TD) - Leisure Battery/Fridge not working


drew-boy007

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Hi All,

 

Recently (2 weeks ago) my MH fridge stopped working on 12V and I discovered over the course of the weekend (no EHU this time out) that the leisure battery (2 off under passengers seat) discharged and did not recharge with the engine running.

 

I am not 100% sure that the charging DID work as I've only taken the beast out three times for overnight+ and always charged the whole van before any trips using the EHU at home. But, I didn't notice any issue prior to this weekend.

 

I'm familiar with electrics (not expert) and I have checked all fuses in the 4 fuse boxes on the MH, investigated the symptoms and I think that there should be a relay that would, on starting the ignition, trigger the alternator to feed not only the Starter battery but also the leisure battery. I think this is called a Split Charge Relay.

 

Some threads I've seen suggest that the fridge may by intimately involved in the set up and this has shaped my thoughts/approach. I've focussed on tracing from the coach builders fuse box (behind the drivers seat). Here I found one connector pin that I think should have had power when the the engine was running but which didn't.

 

I couldn't trace the route of the wire due to being without the right tools.

 

I looked in the engine bay for a relay with a connected fuse which the owners documentation suggested there should be but couldn't find one.

 

Before I investigated further I wondered if any of you guys could guide me as to the likely location of the relay?

 

I realise that I've got no photos but the MH is in its secure compound whlst I'm languishing at home!!

 

I'll get more info during the week but thought it might help if I describe the problems as this may assist with virtual diagnosis! :-D

 

Thank you all

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Hi Andy,

 

Welcome to the forum.

 

I am not familiar with the detail of the wiring of your MH, so I unable to be specific regarding relay locations.

 

When your MH engine is running, the electrical loads are supplied by the alternator, the main output of which is permanently connected to the starter battery.

In order to supply the fridge and charge the habitation or service battery, they need to connected to the starter or engine battery.

A common method of achieving this is to connect the fridge to the starter battery via a relay (fridge relay), and to link the two batteries together via a split charge relay. The split charge relay allows the alternator to charge the habitation battery in addition to the ,starter battery.

 

Operation of the fridge relay is usually from D+, which is a common name for the alternator field connection. This is a sensitive point on the alternator system, and if overloaded can stop the alternator working. To avoid overloading the D+ connection, the split charge relay is often operated from the fridge side of the fridge relay. More briefly, D+ which comes live when the alternator is working, operates the fridge relay, which in turn operates the split charge relay.

 

Relay location can be MH model specific. For some earlier Ducato based MHs, a popular location was under a plastic cover at the rear of the engine bay. There will also be associated fuses possibly as high as 20A for the fridge, and 50A for the split charge supply. This latter fuse at least should always be close to the starter battery. An alternative location for the relays is for them to be included in the converters fusebox, The split charge fuse should still be close to the starter battery.

 

Your symptoms suggest that either of the fridge or split charge fuses has blown, or that the D+ connection from the alternator is faulty. Other possible causes of failure are corroded relay connections, faulty relay(s), and a faulty link between the starter battery negative, and the habitation battery negative.

 

Alan

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Andy,

 

The above is a good list of points to check from Alan but one other point to add.

 

Some manufacturers where know to cut back on wire use and run the fridge wiring off the leisure battery rather than from the starter battery. This is all very well until the split charge relay and/or fuse fail then the fridge will still run on 12 volts from the leisure battery with the engine running BUT the leisure battery will no longer be charged from the alternator so the fridge will discharge the leisure battery in a short time. This sounds to be what is happening in your case.

 

As Alan has suggested look around the engine bay for a covered junction box containing relays and fuses and check them all. If it isn't obvious then look at the starter battery positive terminal and try to identify any none Fiat wiring and follow that.

 

Keith.

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I’m not sure if it will help, but I THINK a CI Riviera 181’s habitation electrical system will be based round Nordelettronica equipment.

 

I’m not familiar with Nordelettronica kit, but it might mean that relays (split-charge etc.) are integrated into a ‘black box’ somewhere rather than being individually located.

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Hi Keith,

 

Thanks for this additional point.

 

From memory, the fridge DID work on 12V when the EHU was connected - Yes, I was still experimenting with how it all worked!!

 

I also recall that, during our summer hols 3 weeks ago now that the fridge did also work on 12V when not on the EHU but it gave up the ghost at some point between us arriving and us leaving. Sadly the gas also packed up but, with the help of this forum, I identified a loose connection to the control valve which, when repaired, gave us back gas operation.

 

So, I do think that the fuses you both mention are my first point of investigation but, in light of my lack of precise detail, I'll have to go step by step through the fault finding / repair process and test at each stage to help me understand these systems better.

 

I'll be sure to respond pint by point so others can benefit from my findings - I'm learning that MoHos are not always the same or follow a common set of design rules! *-)

 

Loving the forum though! :-D

 

Cheers

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Hi Derek,

 

I think you're right.

 

There are 4 fuse boxes - 1 in the engine bay (containing the big fuses that Alanb referred to); 1 either side of the passenger compartment and 1 more behind the drivers seat. This last one is the CI installed box and contains fuses and a PCB to which all Hab electrics appear to be connected.

 

All fuses in the 2nd, 3rd and 4th locations are intact.

 

There is one connector that I was able to test and to which I'd have expected the Split Charge signal to travel down but this had no voltage - ign on or off. I'm going to trace this forward once I've checked fuses in the engine bay if the fuses are all intact.

 

Either way, I'll report back the detail I find.

 

Thank to all you guys for your support.

 

Cheers

:-D

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drew-boy007 - 2020-09-08 8:21 PM

There is one connector that I was able to test and to which I'd have expected the Split Charge signal to travel down but this had no voltage - ign on or off.

And what about when the engine is actually running? That is the only time a split charge should be live!

 

Keith.

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drew-boy007 - 2020-09-08 8:14 PM

 

I also recall that, during our summer hols 3 weeks ago now that the fridge did also work on 12V when not on the EHU but it gave up the ghost at some point between us arriving and us leaving.

 

To me this reads like you are expecting fridge to work on 12v when parked up with engine off, that's not how they work if a three way.

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drew-boy007 - 2020-09-08 8:21 PM

There are 4 fuse boxes - 1 in the engine bay (containing the big fuses that Alanb referred to); 1 either side of the passenger compartment and 1 more behind the drivers seat. This last one is the CI installed box and contains fuses and a PCB to which all Hab electrics appear to be connected.

:-D

 

Andy,

 

If the fusebox that you are looking at in the engine bay contains relays, several maxi blade fuses, and mini blade fuses, it will be the engine bay fusebox for the base vehicle only. The fuses to which I was referring may be inline fuses, or mounted on a small fuseblock.

 

Alan

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Drew-boy! if you can find my old post from earlier this year I had a problem with my 12v supply. Not the easiest problem to fix. Before you do anything else, if you have no 12v at the appliance with the engine running then double check the plugs under the fuse control panel behind the drivers seat.

I thought there was only 1 large plug for the fridge but there are 2 and I only found 1 1st time looking. The 2nd plug is more towards the centre of the board, not on the edge. Make sure all plugs are pushed up firm.

If yours is wired the same as mine then all connections go back to this panel and there are no more fuses.There is no connection back to the leisure battery.

 

Clive

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Firstly, my thanks to all those who have contributed to help my cause!

 

I've included photos that are accessible via https://drive.google.com/drive/folders/1MX0B7MpKFGtnWYOFA2lNy_AX2YcP9mpt?usp=sharing

 

 

I spent a few hours trying to trace the problem today and have a report that, whilst not conclusive, does help to eliminate some causes.

 

I referred to the attached diagrams after an initial physical search and I've recorded the results.

 

The fridge type is a Manual Energy Selection (MES) Dometic RM7XX1 (probably RM7401).

 

The physical search involved a long look around the engine bay which revealed little except for a dangling cable - see photo - next to the battery which looked clean (as though it had been only recently disconnected) but there was nothing obvious that it would have become disconnected from. I plan to remove the battery tomorrow [stupidly didn't take sockets/spanners with me today] to check behind it.

 

I then opened up the Habitation fuse box/wiring nest and did checks there. I refer to the attached diagrams in the following report. All done with the help of a multimeter (only shows volts in units as opposed to any decimal places).

 

Leisure batteries show 9 Volts - they're not recharging so this is not a surprise but I needed this to allow me to distinguish/confirm that other readings were from the leisure battery.

 

Wiring Schematic

JP11 is the input connector from the car battery/alternator. I got the following readings from the connectors insider the plastic male connector block on the end of the incoming trio of wires [figures in brackets are with the engine running]:

1 - 12 Volts (13.4 volts) as expected

2 - 12 Volts (13.4 volts) as expected

3 - 0 Volts as expected (0 volts) NOT as expected

4 - Earth - 0 Volts (0 volts) as expected

 

JP8 is the output from the board to the fridge. I got the following readings from the spades inside the female connector on the PCB:

1 - Earth - 0 Volts (0 volts) as expected

2 - 9 Volts as expected

3 - 9 Volts NOT as expected due to not having an AES fridge and so NOT expecting to register any current on this spade.

4 - Earth - 0 Volts (0 volts) as expected

 

J6 = D+

I'd expected to get a reading off the spade terminal shown in the photo of the inside of the control panel but I didn't AND there is nothing connected to it - just the bare spade connector which doesn't seem right or logical. But, equally, there is no wire inside the control panel box that appears to be in need of a spade to connect to!! Maybe I'm demonstrating now why I'm not an Auto Electrician!! (lol)

 

After all this, my deduction was that the 1 Amp fuse shown in the Wiring schematic after the ignition switch (Key symbol/D+) may have blown.

 

I traced the cables from J11 back outside the control panel box, around the battery charger (under the drivers seat) and into a wrapped bundle of 3 wires (large Red, large black and smaller blue - presumably the one that carries the smaller current from ignition to the relay). This bundle then disappeared under the floor. I THINK that it then re-appears by the clutch pedal before winding its way behind the dashboard to the RHS and out into the engine bay presumably to the battery/alternator.

 

I took the dashboard apart/off and found two inline blade fuses but these were both intact and nothing to do with the feeds I was investigating

 

:-(

 

So, I'm now stuck!!

 

Clives advice/thread was useful and I think that I have connected all connectors soundly but I can't honestly identify the one that Clive refers to. so, Clive, if you're able to identify the one that caused your problems from the diagram of the Interconnects, I'll go back and double check tomorrow.

 

Having read the link that Robinhood provided the bit about the buzzing caught my eye. Whilst we driving on hols in August, there WAS an intermittent buzzing which I put down to the rear garage door having not closed properly. BUT, it may be that this was a relay in the process of failing. It sounded probably a dozen times in the space of a day and stopped after I'd adjusted luggage in the garage and re-closed the door in the evening. I put 2 + " together and assumed, possibly foolishly, that this had stopped the buzzing. It could be that the noise was a relay.

 

So I may have another issue to explore!!

 

My thoughts now are that I need to:

1. Find the 1 Amp fuse and check if it is blown

2. If this fuse is not behind the battery and is buried elsewhere, I may just give up and run new wires.

3. Check the fridge relay!!

 

Again, thanks for all the help. I hope my approach as explained helps others identify and fix problems they may have.

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Drew-boy!I Will be going to my van Sunday. Not quite sure what the plug reference is for one that is not very visible. I replaced the unit some years ago and will have to check the reference tomorrow.

The buzzing sound is a buzzer not a relay on the back of the centre panel on the unit where the control Knobs are. Mine is a auto changeover Oven/Fridge/freezer 7series again not sure which one.

Plug reference JP4 stopped my buzzer going off when I re-inserted the plug that nad come out.

This is why I thought that my problem was fixed, but there was still no 12v at the rear of the unit. 2 weeks after trying everything I could think of, started again at the rats nest under the fuses and found the second plug that had come out.

It is awkward but for peace of mind you need to pull up the top of the fuse control unit as far as you think is reasonable without any plugs being pulled out and check every socket under the board pushing on the plugs that are still in place as they look deceiving and could be just hanging in there. Also look in the bottom of the rats nest with a torch to see if you have missed anything.

Sorry if it sounds like I am telling you to do the obvious but knowing what you are going through and it taking me a long time to find my fault.

 

Clive.

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Hi Clive

 

Really appreciate your advice. Thank you.

 

I'm going back to the MH today to do a couple more checks and I'll be sure to run through your list of checks too.

 

If the problem still exists, having slept on it, I think I'll run a test wire from a switched connection in the engine bay or fuse box directly to the JP11 socket, connector 3 (the D+ connection point), see if the relay on the control panel is triggered and, if that is triggered, check the leisure batteries for voltage i.e. are they being charged.

 

If they aren't being charged I'll need to check/replace the relay I think.

 

Then, if the fridge does work, all good. If not, I'll investigate that further following your earlier advice.

 

Good luck with your investigations.

 

 

Cheers Andy

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Andy,

 

1. In your photo of the battery area, are the two x 2 pole connectors a male & female pair?

 

2, Does your alternator (battery) warning light illuminate when ignition is switched on, and go out when engine is started?

 

3. Does your oil pressure light illuminate, when the ignition is switched on, and go out when the engine is started?

 

4. Do the colours of the wires to the connectors match?

 

5. If the connectors match it is probable that the connectors carry the D+ connection from the alternator, should be connected.

 

On my 2006 2.8JTD PVC, there is a 2 pole connector in the same position. It carries the D+ connection and the oil pressure warning light connection.

About 10 years ago, I discovered that my CBE 12V control system had been incorrectly connected to D+, by the converter. I moved the connection to ignition +ve, so that the installation matched CBE's insallation instructions. I am therefore quite certain that the D+ on my vehicle passes through connectors in the same location as those found by you, also agrees with Fiat eLearn wiring diagram. It seems quite possible that your earlier vehicle will be similar in this respect.

 

It is possible that you alternator would start generating without the D+ connection, when thae engine is revved. This should not be relied on, and generation is normally possible at tickover.

 

Alan

 

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Andy,

 

I have just read your latest post. I must advise against your propsed test while your habitation/service battery is only showing 9V. If you close the split charge relay while this condition existe, there is a possibility of excessive current flow into the service battery. This could at the least blow the 40A? fuse for the starter battery connection, but there is also the possibility of damage to the disstribution board.

 

Alan

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Alanb - 2020-09-13 10:49 AM

 

Andy,

 

I have just read your latest post. I must advise against your propsed test while your habitation/service battery is only showing 9V. If you close the split charge relay while this condition existe, there is a possibility of excessive current flow into the service battery. This could at the least blow the 40A? fuse for the starter battery connection, but there is also the possibility of damage to the disstribution board.

 

Alan

 

I agree with Alan, remove the leisure battery(ies) and try charging them off the MH with a stand alone battery charger. They ideally should show a voltage of well over 12.5 volts several hours after charging before refitting them. If they will not charge or hold the charge then they are damaged beyond recovery and must be replaced.

 

Keith.

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Thank you both for your warning. I took a charged battery with me, connected it up, connected also between the fuse panel and the JP11, T3 connector and heard the relay work, checked the charging to the new battery and it was reading at over 13 volts. The control panel in the MH showed that the battery was showing 2/3 charge as opposed to Red (warning) and, to to it all, the fridge is still working and will work when the engine runs.

 

I may never find the fault but I now know, thanks to you guys guidance and advice, a lot more about the MH electrical system and have fixed the problem with a fridge that I feared I may have to replace.

 

Grateful thanks to all.

 

Photos of the eventual fix to follow next week.

 

 

 

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Andy,

 

Just to clarify a comment in your last post, are you saying the fridge works on 12 volts even WITHOUT the engine running?

 

If yes then this is the reason for your leisure battery going flat. The fridge draws possible 8 - 10 Amps and this will flatten your battery in a few hours without the engine running to offset it.

 

Keith.

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Hi Keith,

 

I've got parts coming midweek with which to fix the relay supply issue and so I'll test properly and reply to you on your last point then.

 

I'm reading up about the Dometic RM7XX1 L in the meantime to ensure that I understand how to establish if and how any more issues exist.

 

I'm hoping that all that has happened is that one fused connection has failed and taken out the relay trigger and the source of supply to the fridge and batteries. If it is not this then, I should know this week.

 

The forum has been so helpful in explaining things and guiding me and increasing my confidence enough to tackle the situation. I really am very grateful. This is an excellent example of just how one would want a forum to be.

 

Cheers

 

Andy

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