CBE DS 300 (304TR) and Dometic Fridge not operating on 12V or Gas

[tealandsilver]

Good afternoon everyone. I have read through many of the posts here and elsewhere looking for info on my problem!

 

Chausson Allegro 93 (2008)

 

I have a fault with the Dometic Fridge Freezer model RM7855 L in that it doesn't now work on 12V or gas but OK on mains hookup. The fridge is always left on auto, selecting the switch manually to 12V results in a red led and switching to gas gives an intermittent led. The van hasn't been used for 8 months until a week ago so I am not certain how long the fault has been there for. I have carried out several checks; there is no 12V supply for the DC heater at the back of the fridge chassis whilst selected to 12V with either engine off or running. There is a 12V supply to the other terminal block at the fridge rear (small cross section wiring).

The fuse (Fuse 6) within the 12V CBE DS304TR distribution box is OK, I measure 12V at the fuse itself, but there is no supply at the 6 pin multi connector on the PCB (Pin 3 bottom lhs).

I removed the DS304TR from the van (with great trepidation I may add) and can see no evidence of overheating or oxidation on the pcb. There are miniature relays (Tyko) soldered to the board, I'm wondering if one has failed. I see that I could obtain a replacement relay from the internet but suspect that it'd be a swine to replace.

 

Presumably a signal comes from the fridge back to the relay to operate it and pass the high current to the DC heater, when 12V is requested?

 

Anyone know which pin on the multi-connector the signal comes into the fusebox board on?

 

I'm at the stage now of thinking of disconnecting the 12V at the fridge rear and putting a temporary supply in straight from the incoming terminal on the fusebox to rule out the fridge being faulty, does anyone see any issues with that?

 

I am also wondering if I could rewire and use the electric step supply, through a relay (maybe a step too far!)

 

Where would I source a replacement DS304TR board from?

 

Finally, I am struggling with no decent drawing (I've got a basic one for the Chausson electrics). Several posts refer to info on the Marcel (Edit: Marcle Leisure) site but the info seems to have been removed. Anyone with info on the CBE DS300 and it's derivatives, that they could share, would be really appreciated!

 

Information, advice and suggestions would be very welcome!

Apologies for the very long post

 

David

[Derek Uzzell]

Welcome to the Out&AboutLive forums, David.

 

As stated on the current Marcle Leisure website

 

https://www.marcleleisure.co.uk/

 

the original business located near Much Marcle in deepest rural Herefordshire ceased trading in April 2019 and the present company using the same name has an address in Cheshire. So any forum links to Marcle Leisure prior to 2019 will either no longer work or will select a completely altered website.

 

This link is to an Instructions Manual for a CBE PC-100/200 ‘kit’ and includes information on the DS-300 Distribution Box.

 

https://www.libble.eu/cbe-pc-200-ds-300/online-manual-824524/

 

The “TR” suffix of your CBE DS-304TR Distribution Box indicates that it was a DS-300 variant produced for "TRigano” motorhomes (Chausson is part of the Trigano Grooup), The only source of an exact replacement is likely to be via a Chausson dealership.

[Robinhood]

If you haven't got hold of this so far, it might prove useful:

 

https://www.4mcculloch.co.uk/images/mediator/559/599523023.pdf

 

(Service Instructions including the RMT7855 - though this is the "Tech Tower" with the oven, The oven is essentially "tacked on" to the top of the fridge freezer, and I'm pretty sure all the info referring to the fridge freezer and ignoring the oven will be relevant)

 

Having struggled for quite some time with a friends RMT7655 my first point of suspicion would be the fridge PCB, and the relays thereon (though the symptoms I was chasing were different to yours - a fix was finally achieved by replacement of a 12V/230V relay on that PCB, though diagnosis was a long task, the repair wasn't - though not all PCBs and faults thereon are repairable).

[tealandsilver]

Hi Derek,

 

thankyou for the quick reply and welcome.

 

Your explanation would explain the broken links to Marcle! Your post suggests that you attached a link for me to an instruction manual? Unfortunately I can't find it in your post, could you kindly resend it?

 

regards

 

David

 

Derek Uzzell - 2020-09-25 6:54 PM

 

Welcome to the Out&AboutLive forums, David.

 

As stated on the current Marcle Leisure website

 

https://www.marcleleisure.co.uk/

 

the original business located near Much Marcle in deepest rural Herefordshire ceased trading in April 2019 and the present company using the same name has an address in Cheshire. So any forum links to Marcle Leisure prior to 2019 will either no longer work or will select a completely altered website.

 

This link is to an Instructions Manual for a CBE PC-100/200 ‘kit’ and includes information on the DS-300 Distribution Box.

 

The “TR” suffix of your CBE DS-304TR Distribution Box indicates that it was a DS-300 variant produced for "TRigano” motorhomes (Chausson is part of the Trigano Grooup), The only source of an exact replacement is likely to be via a Chausson dealership.

[tealandsilver]

Hi Robin, thankyou for your reply. No I haven't come across this manual so it will be a useful aid. I did wonder how to get into the control panel on the fridge, this looks as if it will help. I'll print it out so that I can refer to it as I go. The pile of bits from my van is getting ever bigger!

 

regards

 

David

 

Robinhood - 2020-09-25 6:56 PM

 

If you haven't got hold of this so far, it might prove useful:

 

https://www.4mcculloch.co.uk/images/mediator/559/599523023.pdf

 

(Service Instructions including the RMT7855 - though this is the "Tech Tower" with the oven, The oven is essentially "tacked on" to the top of the fridge freezer, and I'm pretty sure all the info referring to the fridge freezer and ignoring the oven will be relevant)

 

Having struggled for quite some time with a friends RMT7655 my first point of suspicion would be the fridge PCB, and the relays thereon (though the symptoms I was chasing were different to yours - a fix was finally achieved by replacement of a 12V/230V relay on that PCB, though diagnosis was a long task, the repair wasn't - though not all PCBs and faults thereon are repairable).

[Robinhood]

tealandsilver - 2020-09-25 8:09 PM

 

.... I did wonder how to get into the control panel on the fridge, this looks as if it will help

 

regards

 

David

 

 

(assuming similar to that I worked on), the control fascia is held via screws accessible when the control knobs are pulled off.

 

It's all slightly fiddly, but the PCB is detachable and removable with care through the resulting gap (though best to take a photo or two of the wiring).

 

As I've said, your symptoms are rather different from the one I diagnosed, and certainly might be due to lack of 12V input, but the wiring diagrams in the booklet should at least give some idea of the points to test.

[tealandsilver]

Thankyou Robin. I will follow through with this option tomorrow. One thing I've gleaned from your service manual is that my fridge/freezer is of the AES type (Auto Energy Selection). According to the general drawing for the DS300 there should be a bridge fitted across FA2 and FA3 spade terminals. This looks as if it would bridge out the relay on the DS300. There is no bridge fitted in my van. However I had the 240V heating element replaced on the fridge last year as it had burnt out. I'm now wondering if it was removed at then and not replaced. However I can't see any scratch marks on the terminals to indicate one had been fitted. I'm now thinking maybe I should short across it to see if I get the 12V back?

 

regards

 

David

 

Robinhood - 2020-09-25 8:45 PM

 

tealandsilver - 2020-09-25 8:09 PM

.... I did wonder how to get into the control panel on the fridge, this looks as if it will help

 

regards

 

David

(assuming similar to that I worked on), the control fascia is held via screws accessible when the control knobs are pulled off.

 

It's all slightly fiddly, but the PCB is detachable and removable with care through the resulting gap (though best to take a photo or two of the wiring).

 

As I've said, your symptoms are rather different from the one I diagnosed, and certainly might be due to lack of 12V input, but the wiring diagrams in the booklet should at least give some idea of the points to test.

[Derek Uzzell]

tealandsilver - 2020-09-25 7:54 PM

 

Hi Derek,

 

thankyou for the quick reply and welcome.

 

Your explanation would explain the broken links to Marcle! Your post suggests that you attached a link for me to an instruction manual? Unfortunately I can't find it in your post, could you kindly resend it?

 

regards

 

David

I’ve inserted the missing link into my earlier post (Sorry about that) and have repeated it below

 

https://www.libble.eu/cbe-pc-200-ds-300/online-manual-824524/

 

I think this CBE Manual was all that was on the old Marcle Leisure website for the CBE DS300 Distribution Box and I haven’t come across anything more explanatory.

 

What the Marcle Leisure website did warn of was the need to specifically identify the Box’s reference number (DS-304TR in your case) when ordering a replacement as the Boxes with a reference number suffix are ‘bespoke’ and, if a different DS300 Box were installed, there would be no certainty that all the features would work properly.

[Robinhood]

tealandsilver - 2020-09-25 8:58 PM

 

Thankyou Robin. I will follow through with this option tomorrow. One thing I've gleaned from your service manual is that my fridge/freezer is of the AES type (Auto Energy Selection). According to the general drawing for the DS300 there should be a bridge fitted across FA2 and FA3 spade terminals. This looks as if it would bridge out the relay on the DS300. There is no bridge fitted in my van. However I had the 240V heating element replaced on the fridge last year as it had burnt out. I'm now wondering if it was removed at then and not replaced. However I can't see any scratch marks on the terminals to indicate one had been fitted. I'm now thinking maybe I should short across it to see if I get the 12V back?

 

regards

David

There's no way to tell at distance how the thing was originally wired, or indeed if it has been changed since then, but you might like to read the thread below, which details almost the exact reverse of your issues:

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/CBE-DS300-distribution-box-/53457/

[Robinhood]

I missed the edit, so:

 

In case it isn't clear, the function of the "bridge" for AES fridges is to bypass the CBE components' logic for 12V (cooling) supply to the fridge, and rely on the switching logic in the AES fridge to enable it. (This applies only to the cooling supply, there should be a separate permanent control supply to the fridge (which I think you've found)).

 

I can't get my mind around this causing all your symptoms (without a further wiring change or fault), but it is probably worth a try. With the bridge in place, the 12V cooling should (I think) work whether the engine is running or not as long as the fridge is manually switched to 12V (not Auto).

 

The gas not working (the intermittent light probably indicates attempted ignition) is quite another thing, and I think I would have expected this to be controlled from the permanent connection not associated with the bridge.

[tealandsilver]

Thankyou Derek and Robin. The manual on the CBE PC 200/DS300 and the Dometic service manual enables me to make sense (just about) of the electrical pictorial schematic supplied by Chausson.

 

Task for this weekend will entail looking at the fridge electrics at the fridge control panel,

 

cheers

 

David

[jb6981]

tealandsilver - 2020-09-25 6:03 PM

 

... There is a 12V supply to the other terminal block at the fridge rear (small cross section wiring).

The fuse (Fuse 6) within the 12V CBE DS304TR distribution box is OK, I measure 12V at the fuse itself, but there is no supply at the 6 pin multi connector on the PCB (Pin 3 bottom lhs). ... Anyone with info on the CBE DS300 and it's derivatives, that they could share, would be really appreciated!

 

Information, advice and suggestions would be very welcome!

 

I have a Hobby 725, 2006, I have owned this van from new. The CBE distribution box is a DS-300HB (CBE 209009). I am on my third box, which has recently failed.

 

The first failed after three months of ownership and was replaced under warranty by Brownhills, Cannock. That, second box failed about nine months later and was again replaced under warranty in 2007. This third box has lasted a good few years but has now failed in exactly the same way as the first two.

 

The symptoms are; the electric step fails to retract automatically on engine start, the leisure battery is not charged when the engine is running and there is no 12 volt to the fridge. I believe the cause for failure is a faulty relay which as you say is soldered to the circuit board.

 

If it is the DS300 at fault, you have two options: source a replacement from a Chausson dealer or have it repaired.

 

Apuljack Engineering have a product and repair list on their website: http://www.apuljackengineering.co.uk/product_repair.html

 

They list the DS-300HB and the DS-300TR in the CBE section. I sent them an e-mail enquiring about their service, they replied

 

"Yes we can help you with this.

 

The DS300 is one half of the distribution system in your vehicle, and it is paired with a control panel, and we offer a fixed price repair for the system of £220 (exVAT and shipping) which includes all spares and labour to fully investigate, repair and test the two items. Work is covered by a 12 month warranty. Work will take 1-2 weeks to complete.

 

Please complete our customer order form and send the units to us:

 

http://www.apuljackengineering.co.uk/order_form.html" end quote.

 

I suspect that, from your discovery of no 12 volt at the 6 pin multi connector, your box is faulty. It would not surprise me based on my experience of CBE hardware. I would never buy another van with CBE electrics; A German van with Italian electrics is not a good combination.

 

 

 

[Derek Uzzell]

A significant attraction of CBE equipment for motorhome converters is its cost and the modularity that makes it straightforward to install.

 

Apuljack Engineering's price of around £270 for testing/repairing a CBE control panel and Distribution Box is not unreasonable, but a complete brand-new ‘universal’ CBE PC200 kit can be obtained for £370.

 

http://www.rainbow-conversions.co.uk/cbe-motorhome-caravan/cbe-pc200-kit.html

 

(Obviously, that’s not necessarily going to help if a motorhome has a ‘bespoke’ panel and DS box, but it gives an idea of how cheap the equipment must be when a converter buys in bulk.)

 

I’m startled that you have had three DS-300 failures - I owned a 2005-built Hobby motorhome (with CBE PC100 system) for 9 years and had no problems with the CBE side of the vehicle.

 

There have been a few reports on French motorhome forums of relay failure on the Distribution Box PCB and being DIY fixed, but - given the huge numbers of motorhomes that have been factory-fitted with DS Boxes - I think you’ve been very unlucky and that, generally, the CBE equipment has proven reliable.

[tealandsilver]

Wow, three failures, that's really unlucky. In fairness, this is the first issue that I've had with the electrics in my van over the 12 years I've owned it. The link for repairing the distribution box is helpful, thankyou.

 

I am now treating the faults I've got as 2 unrelated ones, the loss of 12V "cooling" supply due to the board fault and the failure of the gas side due to a combination of stuck/failed gas solenoid valve and ignitor module. Over the years we have always used sites with mains hookup apart from when I visit fisheries for a few hours (which was when we noticed the fridge issue). In reality the faults could have occurred at any time in the past.

[Brian Kirby]

Robinhood - 2020-09-26 10:03 AM............................... With the bridge in place, the 12V cooling should (I think) work whether the engine is running or not as long as the fridge is manually switched to 12V (not Auto)...............

Correct. :-) I know this because our van is supplied as standard with a compressor fridge, but I exercised the option for a three way fridge. I later discovered that the non AES fridge continued drawing 12V power (manual energy selector switch) when I forgot to set the switch to 230V. Assuming this was a fault, when it went to Southdowns for its first service, I mentioned it. The technician emerged a while later with a broad grin and explained that the above link had been left in place, ensuring an uninterrupted 12V supply to the fridge for cooling - so that unless the energy selection switch was turned to an alternative source, the fridge would continue running on 12V whether or not the engine was running. With the link removed, all was OK. So, a missing link might be a possible cause - though it shouldn't contribute to the gas problem - unless the AES supply via the link somehow also feeds the gas solenoid and igniter?

[tealandsilver]

So, interesting day today. I removed the 12V 30A relay at the fridge to enable me to check the connections and coil resistance. Nothing obviously wrong. Replaced the relay and then checked various other connections on both the 12V side and gas ignition module. However on starting the engine with mains disconnected the fridge 12V led changed from red to green and I had 12v at the fridge heating element! Wish I could say for certain what the issue had been as my next step was to fit the bridge to see what happened. Should have tried starting the engine after re-fitting the relay! The circuit seems a bit odd having two relays involved, can't quite get my head round that one.

 

So that leaves me with the gas fault. Spent some time checking connections and doing voltage/resistance measurements.

The gas control valve isn't opening. According to the info from the fridge service manual the valve has two valves in series, electrically operated at 1.5V. The coil resistances are 45 and 47 ohms i.e. as specified. However, the gas control module isn't delivering the 1.5V. Neither am I getting a spark at the burner, despite the led at the fridge control flashing orange all the time. Beginning to look like the Hea Tec module is goosed, although I still have to check the control wiring at the fridge control board. That's for another day!

Thanks Brian for the additional info.

 

Cheers, David

 

 

Brian Kirby - 2020-09-27 6:40 PM

 

Robinhood - 2020-09-26 10:03 AM............................... With the bridge in place, the 12V cooling should (I think) work whether the engine is running or not as long as the fridge is manually switched to 12V (not Auto)...............

Correct. :-) I know this because our van is supplied as standard with a compressor fridge, but I exercised the option for a three way fridge. I later discovered that the non AES fridge continued drawing 12V power (manual energy selector switch) when I forgot to set the switch to 230V............ With the link removed, all was OK. So, a missing link might be a possible cause - though it shouldn't contribute to the gas problem - unless the AES supply via the link somehow also feeds the gas solenoid and igniter?