# Dometic fridge on full power



## lucylocket (Jan 13, 2012)

Our RM 7605L Fridge freezer knob seems to be broken as all the lights are on and freezing up, good for beer but not nice for tomatoes, tried everything to no avail & luckily staff at Laguna Playa Torre Del Mar directed me to Auto-Star Caravanas Almayate. On Friday taking our "Mo" there as the Dometic chap Niko is here from Granada so all being well will be fixed. 
MB & G warranty were not very helpful as we are in Spain so will wait to see how much to fix. They need a phone call to say yes or no but not very helpful when you wait over half an hour for them to answer as they insist the repairer telephones so can't see that happening.  

:arrow: Watch this space for update


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## selstrom (May 23, 2005)

We have had 2 snap, very poor design.

Should only take 5 minutes to repair.

When repaired set and try not to touch again.


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## Pudsey_Bear (Sep 25, 2008)

Pull it off, fill your knobs shaft hole with Araldite and put it back on in the correct position for the way it is set at the moment and leave it for a day or two, then it should be fixed for good, I've had to do 4 knobs now, but once fixed they stay fixed.

TB, behave, and the rest of you.


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## lucylocket (Jan 13, 2012)

*Fridge knob*

Fixed, tried to glue but lights still all on so took "Mo" to Caravans Auto Star in Almayate 3km from Torre del Mar. Dometic & Truma fixers, took half an hour only 18 Euro with tax, happy, snapped at the back beyond the spindle


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## tugboat (Sep 14, 2013)

Kev_n_Liz said:


> Pull it off, fill your knobs shaft hole with Araldite and put it back on in the correct position for the way it is set at the moment and leave it for a day or two, then it should be fixed for good, I've had to do 4 knobs now, but once fixed they stay fixed.
> 
> TB, behave, and the rest of you.


Behave? Moi? Oohlala! :wink:


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## Pudsey_Bear (Sep 25, 2008)

tugboat said:


> Kev_n_Liz said:
> 
> 
> > Pull it off, fill your knobs shaft hole with Araldite and put it back on in the correct position for the way it is set at the moment and leave it for a day or two, then it should be fixed for good, I've had to do 4 knobs now, but once fixed they stay fixed.
> ...


I should have said DON'T overfill the shaft hole as it's ooze out everywhere and might actually jam in one position, which is not good.

You need just enough to account for the wear, I had to do on eat home last year, and I opened it up with drill to allow more Araldite in and make it strongerer, it's still fine, but standard Araldite works better than Rapid for some reason, it just needs to be supported til it goes orf.


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## Baron1 (Mar 9, 2011)

Sorry to tag onto the end of this thread but since the new layout I can't see how to start a new thread!
I have a Dometic RM 7605 L AES fridge with a 12volt heating element fed by two hefty wires which are connected to it via a connecting block.
I was hoping to take a 12volt feed from this to power a 12v TV via a din socket, I checked that I was getting 12v at the connecting block and all ok but after I connected the wires from the din socket there was only 0.6 volts at the block! I disconnected the din socket but still only 0.6 volts at the block.
The van is on hook up with the fridge turned off, my question is, should there be a permanent 12v feed to the heating element when the engine is not running or was this caused by a sticky relay that released whilst I was fiddling about?
Help with this would be much appreciated.
Mel.


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## david-david (Feb 24, 2013)

Baron1 said:


> Sorry to tag onto the end of this thread but since the new layout I can't see how to start a new thread!
> I have a Dometic RM 7605 L AES fridge with a 12volt heating element fed by two hefty wires which are connected to it via a connecting block.
> I was hoping to take a 12volt feed from this to power a 12v TV via a din socket, I checked that I was getting 12v at the connecting block and all ok but after I connected the wires from the din socket there was only 0.6 volts at the block! I disconnected the din socket but still only 0.6 volts at the block.
> The van is on hook up with the fridge turned off, my question is, should there be a permanent 12v feed to the heating element when the engine is not running or was this caused by a sticky relay that released whilst I was fiddling about?
> ...


As far as I was told, it works like this -

On EHU fridge works on 240v - unplug EHU and you must use gas - Gss must be turned off while travelling - turn on 12v while travelling.

So it wouldn't surprise me if the 12v was interlinked to ignition.


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## Baron1 (Mar 9, 2011)

I know that the fridge automatically switches to 12v operation when the engine is running, my question is should there be a permanent 12v feed to the fridge heating element when on hook up?


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## philoaks (Sep 2, 2008)

Yes, there should be a 12v supply to your fridge.

In the good old days there were often two separate feeds to the fridge. One was a permanent 12v feed to run the control side of things and the other was only present whilst the engine was running. This allowed the power hungry 12v element to operate the fridge whilst on the move.

With the latest AES fridges there appears to be just one 12v supply. This runs the control side of things and (when it receives the correct signal from the vehicle alternator) also runs the 12v element when on the move.

I can't find a wiring diagram for your model online but you should have a permanent 12v supply somewhere.

P.S. It won't be feeding the 12v element whilst on hookup as there is a separate 240v element for that but it will still be feeding 12v to the control side.


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## Baron1 (Mar 9, 2011)

Thanks philoaks,
I went out to the van, disconnected it from EHU started the engine and turned the fridge on to auto, it immediately switched to 12v working. I then checked the voltage at the "12 DC heating element" terminal block and it read approx 0.6 volts! I would have thought that with the engine running it should read about 13-14volts...... any ideas??
Mel.


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## rayc (Jun 3, 2008)

Baron1 said:


> I know that the fridge automatically switches to 12v operation when the engine is running, my question is should there be a permanent 12v feed to the fridge heating element when on hook up?


I believe that there will be no 12v to the 12v element whilst on EHU.
I have recently renewed the 12v switching relay on my RMD8051 and am familiar with the circuitry. MH manufacturers do not all connect the fridge in the same way. 
My Adria has a permanent 12v feed to the electronics but the 12v for the heating element is fed from the electtrobloc when the engine is running. This is then switched to the element by the 12v relay when the fridge is set to AES or manually to 12v.


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## rayc (Jun 3, 2008)

Baron1 said:


> Thanks philoaks,
> I went out to the van, disconnected it from EHU started the engine and turned the fridge on to auto, it immediately switched to 12v working. I then checked the voltage at the "12 DC heating element" terminal block and it read approx 0.6 volts! I would have thought that with the engine running it should read about 13-14volts...... any ideas??
> Mel.


On my Adria it would suggest there is a problem in the supply from the electrobloc. The electrobloc has a fridge 12v output which supplies an output when it detects the engine is running [alternator providing current]. This is fed to the fridge via a 20a fuse located close to the electrobloc.


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## Baron1 (Mar 9, 2011)

Thanks Ray,
When you say close to the electrobloc do you mean a separate fuse block? i.e. not actually on the electrobloc itself?
Mel.


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## rayc (Jun 3, 2008)

To clarify: The electrobloc receives the voltage from the engine battery via a 20A fuse adjacent to it. The electrobloc switches the voltage to the fridge when it detects the engine is running i.e. alternator has output. The fridge relay then switches the positive to the element when the fridge is on 12v or AES.
I have tried attaching the relevant part of the schematic but doubt it is clear enough.


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## rayc (Jun 3, 2008)

Baron1 said:


> Thanks Ray,
> When you say close to the electrobloc do you mean a separate fuse block? i.e. not actually on the electrobloc itself?
> Mel.


A separate fuse. On this block close to the electrobloc.


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## Baron1 (Mar 9, 2011)

rayc said:


> I believe that there will be no 12v to the 12v element whilst on EHU.
> I agree Ray, I was suprised when I found 13 volts at the heating element with the engine off, maybe it was caused by a sticky relay???


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## Baron1 (Mar 9, 2011)

rayc said:


> A separate fuse. On this block close to the electrobloc.


Right, I will have a look for something like that tomorrow.
Many Thanks
Mel.


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## philoaks (Sep 2, 2008)

Baron1 said:


> Thanks philoaks,
> I went out to the van, disconnected it from EHU started the engine and turned the fridge on to auto, it immediately switched to 12v working. I then checked the voltage at the "12 DC heating element" terminal block and it read approx 0.6 volts! I would have thought that with the engine running it should read about 13-14volts...... any ideas??
> Mel.


Hi Mel.

Curiouser and curiouser!

As you say, with the engine running and the fridge auto switched to 12v you would expect to see at least 12v across those terminals. A couple of things spring to mind.

I assume you've tested the meter direct across the battery, or similar, to ensure it's working ok.

Do you know if the AES fridge is actually cooling when on 12v with the engine running? It sounds as though the fridge is seeing the sense circuit from the alternator and is able to auto select 12v operation but if the 12v to run the element isn't there the fridge may not realise and therefore not show a fault condition.

I suspect it probably isn't cooling on 12v and this is where your strange readings come into it. I'm not sure where the 12v for the heating element is derived. Prior to AES fridges it would have been probably from the engine battery via a relay which would be operated by the sense output from the alternator.

As the AES fridge itself does the "sense" work nowadays then this supply could in theory be derived straight from the engine battery or even the leisure battery. Whichever it is there should be a fuse in the circuit somewhere. To be reading 0.6v suggests that there is still something connected to that wire so you may be looking at a corroded connection or a fuse block that has melted and is barely making a circuit.

If you've got a wiring diagram in the van manual then hopefully it will point you towards where that 12v element supply comes from. That would be my first port of call.

Good luck!

Phil


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## Baron1 (Mar 9, 2011)

As you say Phil, curiouser and curiouser and now even curiouser!!!
Yesterday when I left the van I was getting 0.75 volts across the 12v heating element connector block, I went out this morning to have a look for the fuse that Ray alluded to and thought I'd just check the voltage again before I started.......13.6 volts!
What I still don't understand is, if there is >12v present at the element connector why is the element not heating and the fridge not cooling ..or is there another relay between the connector block and the element that operates when it receives the signal from the alternator?
As for the 0.6 volts that I have been measuring at the connector I have two theories, either the relay that operates when the engine is running was not fully disengaged and letting a small voltage through or the voltage was a back EMF from the permanent 12v supply to the fridge that supplies the light etc.????
Anyway we are off for a few days away and then to the Peterborough Show so that will be a good test for the electrics.
Thanks all for help and advice, I will report back with any news.
Mel.


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## rayc (Jun 3, 2008)

Baron1 said:


> What I still don't understand is, if there is >12v present at the element connector why is the element not heating and the fridge not cooling ..or is there another relay between the connector block and the element that operates when it receives the signal from the alternator?
> 
> Mel.


On my Adria the 12v element supply that arrives at the fridge when the engine is running is switched by a relay attached to the rear of the fridge. The negative supply goes directly to the element whilst the positive is switched through the relay to the element. The relay coil is energised by a signal from the fridge when it is set to 12v or when set to AES and no 230v or gas is detected. 
Photo attached of my relay. It had got hot and melted one of the contacts and the lead to the element had become disconnected. I suggest you measure the voltage at the relay switching contacts. The supply is on Relay contact 30 and the supply to the element on contact 57. The switching voltage, 12v, should be across contacts 55 & 56 to operate the relay. If you disconnect the element at the relay and measure its resistance it should be approx 2ohms.


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## Baron1 (Mar 9, 2011)

Thanks again Ray,
That looks the same as the relay on my Hymer, so just to clarify, the 13-14v that is present at the heating element connector block is switched to the element when the alternator sends a signal to this relay? If that's the case I'm still at a loss as to where the"permanent" feed disappeared to for a couple of days....weird!
Mel.


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## rayc (Jun 3, 2008)

Baron1 said:


> Thanks again Ray,
> That looks the same as the relay on my Hymer, so just to clarify, the 13-14v that is present at the heating element connector block is switched to the element when the alternator sends a signal to this relay?
> Mel.


Sort off. On my Adria the voltage arrives at the element terminal block when the engine is running. The negative goes to the element. The positive is connected to the switching terminal block D+ and the relay. When the 12v option of the fridge is selected then it triggers the relay to feed the positive to the element.


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## rayc (Jun 3, 2008)

rayc said:


> Sort off. On my Adria the voltage arrives at the element terminal block when the engine is running. The negative goes to the element. The positive is connected to the switching terminal block D+ and the relay. When the 12v option of the fridge is selected then it triggers the relay to feed the positive to the element.


I have reattached the drawing that I had placed on here as I seem to have inadvertently deleted all the attachments I have put on any post since I joined the forum.


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