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Dometic 3 way fridge not working on 12v?


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Hi 

There may be a 12v isolation switch fitted  ???? Can you not give the previous owner a ring? He/She may be able to give you a heads up as a lot of changes may have been made over the years from the original 

Hope the diagram helps , but who knows what may have altered by whoever . That may not even be the orignal fridge 

Maybe you can put up some photos of your re connected supply wire (violet) to fridge itself and meter you are using 

Regards

Edited by onecal
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Again I hope this diagram helps your understanding a little more 

The coupling relay and the three-way fridge relay are enabled directly by the D+ signal (or engine ignition key).

The coupling relay recharges the service battery through the alternator with the engine running.

The fridge relay powers the three-way fridge at 12V, with the engine running.

Both relays are excited when the ignition battery exceeds 13.4V and automatically de-excite when the engine is turned off or the battery ignition voltage is below 12.5V.

Old fridge wiring and fuses marked .png

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Hi 

You are very welcome , I am a little puzzled as to your DC supply to fridge as you say you have sorted the gas side of things , as to why you got no reading (12v) on the supply wire (violet cable) marked for you in the photo .

You need to establish were the fridge is getting it's DC supply from? 

Regards

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Antony,

When the fridge is operating on gas does the 'GAS' light illuminate? If yes then the fridge must be getting a permanent 12 Volt supply! Suggest you recheck your voltage reading on the Purple and Black wires as this is the supply for the fridge electronics.

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Hi Keithl

This is my point , it has to be getting a 12v supply from somewhere and that should be from the Violet coloured wire, (as per photo he supplied ,attached, I have marked the test points in for him and the 220V AC )  as Labby and Alanb also pointed out to him .

Regards

 

 

Fridge block connections on old fridge Test .png

Edited by onecal
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Ok, I have tried again and I did get 12.2v when testing the purple (red probe) and white/black (black probe), still not getting anything with the red wire though. It must of been user error yesterday... sorry!

The gas light flashes whilst igniting, then goes solid yellow on ignition, the 220v goes solid green.

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14 minutes ago, antony driffill said:

Ok, I have tried again and I did get 12.2v when testing the purple (red probe) and white/black (black probe), still not getting anything with the red wire though.

You did have the engine running, right?

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Hi, yes I did try it with the engine running and fridge selected to 12v... still no joy. Would there be the possibility that it was never wired up for 12v anyway? There are no extra wires or fuses connected to the leisure battery, all the usual places for relays/fuses have nothing. Is there any other people that have had a 3 way fridge only set up as a 2 way?

Edited by antony driffill
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Hi Keithl, tracing the wiring is a touch awkward, they appear to go upwards to the control panel, then down the inside of a cupboard, under the floor and across to the water heater area under the dining seat. This bunches up with several other cable conduits that ultimately go through to the cab fuse box. Tracing the wiring downwards from the inspection panel they appear to go through into the cupboard below the hob/grill, then across, presumably to the water heater area again.

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Hi

I have supplied a diagram of that for you . See attached 

You mentioned a buzzer >???  I think . Have you a step that rectracts when you start up? 

You say you had a dampness issue also 

Therfore very importanf to check the connection blocks in the fuse box like for example (JP8) 

Fuse box.JPG

Old fridge wiring and fuses marked .png

Edited by onecal
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OK 

You need to check the connector blocks  JP11, JP8, JP9, JP2 etc'  first 

You need to establish you have power as marked on diagram attached (with the engine running)

Happy hunting

Regards

Old Fridge connections marked.png

Edited by onecal
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 When you check the connections on that you will find on the rear of the NE129 ? fuse box  that onecal has suggested you will also need to  check the JP8  connections linked to the  fridge power supply  , RE4 looks like it could be the fridge relay.

If you find the NE129    board is faulty www.apuljackelectronics.co.uk list it in their cataloque as one they repair.

Edited by Labby
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Sorry for my slow reply , got called away , NE 129/NE160

JP 8 (white connector)Fridge Output

1= Negative -

2= Gas Ignition Power +

3 = Output + Fridge Power Supply (AES)

4 = Output + Three way fridge Power Supply 

-------------------------------------------------------------------------------------------------------------------------------

JP 10  (Black connector) From Habitation Battery

1= Input + from Habitation Battery

2 = input + from Habitation Battery

3 = Input + from the battery charger

4 = Negative -

________________________________________________________________________________

JP 11 ( White connector)From Engine Battery /Alt'

1 =  Input + from Engine Battery

2 = Input + from Engine Battery

3 = Input D + from Engine Alternator ( V with engine running)

4 = Negative -

Board for controls.JPG

Old Fridge connections marked.png

Edited by onecal
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Hi, took the fuse cover off (NE129) here are the photos. Tested JP11 and 1 and 2 had 12v, 3 had nothing with or without engine running and fridge set to 12v. As you can see from photos J6 (I presume the bayonet next to the yellow capacitor had no wire attached. J4 and J5 bayonets nothing as well. Does this indicate something i.e its not wired up?

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Edited by antony driffill
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The surest way to check if the leisure-battery is being charged from the motorhome's alternator when the vehicle's engine is running is:

1: Assuming that the motorhome's motor has not been run for a while (say 4 hours) and the vehicle is not connected to a 240V hook-up, use a multi-meter to check the voltage of the battery by connecting the meter across the battery's terminals. If the battery is in good condition and well charged, the multi-meter reading should be around 12.6V.

2: Start the motorhome's engine and take another 'across-terminals' reading with the multi-meter. If the battery is receiving charge, the meter reading will have risen appreciably to around 14V. If the reading measured in 1 above has not increased, the battery is not receiving charge from the vehicle's alternator.

Alternatively, as your motorhome has a NE101C3 control-panel, you may be able to use this to check if the leisure-battery is receiving charge from the alternator. Using that panel is described here

With the motorhome's engine off and the vehicle not connected to a 240V power-supply, I'd expect the control-panel's leisure-battery state-of-charge LEDs to show 2/3 (12.6V) if the battery is well charged.

When the motorhome's engine is started, I'd expect the LEDs to change to 3/3 (above 12.6V) to indicate the battery is now receiving charge from the alternator.

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