Refrigerator 12v supply problem (1 Viewer)

[Scottie2009]

Hi all,
I have an issue with the 12v side of the MH refrigerator. When MH engine is running there is no supply at the fridge front panel or to the stereo sound system. When I remove the fuse for the sound system from the vehicle cab fuse box when the MH engine is running I get 12v supply to the fridge and the stereo.checked all EM50 plugs, Sargent board plugs, stereo plugs fuses etc. I’ve not got a lot of hair left to pull out, any help would be much appreciated.
Thanks

 

[HandyAndy]

Aftermarket stereo?

 

[Scottie2009]

No Andy,
Original Autotrail unit, but I have noted someone has changed the wiring at the back of the stereo, the entertainment receiver has also been removed, but up until last week all worked fine. We off to France next week so hopefully get sorted before the holiday begins, Sargent site says they all on holiday ?

 

[f6c]

Welcome aboard

 

[Scottie2009]

??

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[TheBig1]

ah yet another electrical fault traced back to the awful stereo fitted by autotrail

 

[Landy Andy]

So when you DON’T have the stereo fuse in on the cab fuse board, both fridge and stereo work as they should. But when you put a fuse in the cab fuse board for the stereo neither the fridge or stereo have power. Is that what you are saying?

 

[Chris+Tracy]

Sounds like the fuse powers a relay which is probably faulty.
Try taking the relays out one by one and gently tapping each one on its side.
Usual relay problems are contamination between the contacts.
Just a thought. ?

 

[buttons]

Hi and Welcome….

 

[The Dotties]

No Andy,
Original Autotrail unit, but I have noted someone has changed the wiring at the back of the stereo, the entertainment receiver has also been removed, but up until last week all worked fine. We off to France next week so hopefully get sorted before the holiday begins, Sargent site says they all on holiday ?

I had a small problem with my Sargent unit yesterday, and phoned them.
They do a split holiday rota so some peeps are there. Just be patient and they will answer. (They are very good)

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[Landy Andy]

Is this because the stereo has been rewired to take power from the hab battery so doesn’t flatten the starter battery. So possibly the stereo vehicle fuse may not need to be fitted. Just a thought.

 

[pappajohn]

That sounds like a N/O relay has been replaced with a N/C relay.
Pull the supply voltage, the relay defaults to closed.

 

[Scottie2009]

Hi all,
Thanks for the suggestions; I’m going to have another look tonight and tap some relays.
When working correctly the Stereo has 2x 12v supplies; 1 from the ignition side to the main connector A positive 12v and the other supply has been sourced from under the passenger footwell at a plug which gives a 12v alternator fed supply to the fridge; this supply’s the stereo via a relay to the parking + terminal.(Not sure why!!!!) I just find it bizarre that somehow the vehicle side fuse is affecting the habitation side supply, is there a change over relay somewhere possible?

 

[ambulancekidd]

A Ducato normally has no power to the radio when the engine is off, it would appear that someone has been bodging the wiring to get the radio to work whilst the engine is off.
If I was you I'd set about removing the old wiring & rewire the whole thing.
Try if you can identify it to leave original wiring in place. Your radio is designed to have two 12v feeds, one will be permanently live, this one keeps the memory of radio stations etc & the other should only come on with the ignition, remember that there is no position one as you get in better (all other) vehicles, that would normally be the setting for the radio when you've got the engine off, why Fix It Again Tony (FIAT) do this is a mystery.
We also have a Ducato based vehicle & the wiring drives me nuts, you couldn't follow them if they had the trots!

 

[138go]

Fiat use the CanBus to send information about whats happening to the vehicle. Makes far more sense than running wires all over the place. If you need the radio to stay on in the cab then use one of the many CanBus interfaces which will give you the ACC feed and fit a delay relay. I did it for a Pumpkin SatNav I fitted so it would stay on after you turned the ignition off. The relay had an adjustable time setting upto 6 hours.

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[Scottie2009]

Thanks to you all again for all the tips.
I have contacted Sargent today and after a fair wait got through and they seemed very helpful, sending me wiring diagrams to try tracing out.
I have now admitted defeat and booked an auto electrician to diagnose, 1 week to go before setting of to France so fingers crossed.
Hope you all have a great summer where ever you are
???????????

 

[TCG]

ah yet another electrical fault traced back to the awful stereo fitted by autotrail

Hardly a fair comment when the OP clearly states that the original wiring had been messed with and the entertainment receiver has been removed. I’m not suggesting that the stereo unit isn’t crap, we have changed ours... but hardly the fault of autotrail that some idiot has screwed about with the wiring

 

[Chris+Tracy]

Ours works fine and works when the ignition is off and keys out.
Turns itself off after 2 hours or if the vehicle battery goes dowh below 12V (but it never does!)
Very useful for plugging in the mifi. ???