Fridge not working on 12 volt - Motorhome Forums, Motorhome Discussion, Motorhome Chat

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post #1 of 5 (permalink) Old 13-05-2019, 17:30 Thread Starter
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Fridge not working on 12 volt

I have a Dometic RM 7291 L fridge that will not work on 12 volt with the engine running, when switched to battery it makes a quite loud buzzing noise rather like a relay not latching. It works ok on gas and mains power, I thought the P.C.B was faulty so purchased anew one (£180.00).
I fitted it and the fault is still there. I have 14 volts at the PCB connection but when switched to battery (from fridge turned off) the volts drop to 5 volts and the buzzing starts. I have checked the fuse and made sure it’s ok plus made sure the contacts are clean and tight.

Has anyone had a similar problem, if so I would appreciate their experience and if they resolved it.

Kind Regards John.
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post #2 of 5 (permalink) Old 13-05-2019, 21:36
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Gosh that was an expensive no-fix John!

There are always fridge posts so I'm sure someone will be along soon with their knowledge.

And welcome!

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post #3 of 5 (permalink) Old 13-05-2019, 21:57
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Probably a failure of the relay that dictates when power can go to the fridge............

Not expensive to replace it is pull and then pug the new one in job done normally..... can't give more specific advice about the location etc without advice about what MH you have.....

Welcome to the forum anyway I hope tht you give us some more details so that we can give more specific advice.

Remember Jo Cox and what she stood for.

Any comments above are only MY OPINION and should be read as that.
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post #4 of 5 (permalink) Old 19-06-2019, 20:02
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John, did you get anywhere sorting that out? I possibly have a similar issue.
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post #5 of 5 (permalink) Old 20-06-2019, 07:43
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The relay that directs 12 volts to the fridge (for temperature maintenance) is usually in the engine compartment. I know mine is, and it also operates the auto step retract.

The OP said he was getting a buzzing noise, and I assume he meant from the fridge itself.

As I understand things, a fridge has 2 12volt supplies. One which comes on with the hab electrics and allows the controls and interior light to work. The other with the engine running, and maintains the temperature whilst driving.

I'm daft and proud of it.
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