Vehicle power supply and fridge issues

Your fridge requires a 12v supply to allow its control circuitry to work. Additionally, your car engine needs to be running to energise the fridge in 12v chilling mode.

So, either switch on your van’s 12v services at the master switch, or, if your fridge has an option to run its control with AA batteries, you can use that.

And plug in the car and start the engine.

The, switch the fridge to 12v on its control panel. Some models of fridge will do this automatically.

Remember that a fridge will do little more than hold an already low temperature when ringing on 12v.

We have a fridge thermometer in ours, which tells the stark truth that our fridge struggles in warm or hot weather. The absolute maximum storage temp is 8deg C, but really needs to be 5deg C for normal use. Having dialogues this with the manufacturer it’s clear that we can expect little more.

To verify if there is a fault, and start to identify where it might be, connect your caravan to a different vehicle where the towing electrics are known to work correctly. You can then observe whether there is any change in the lights or cooling function and eliminate the car or the caravan from your quest.

Not all fridges are wired internally to power the control panel when switched to 12v DC from towing vehicle. A couple of minutes search on the Internet should turn up a circuit diagram for your fridge, and you can follow the circuit to find if contol panel is supposed to be powered or not.  Mine isn't.

Conversely, some caravans are wired such that turning off the 12v caravan power master switch does not turn off the fridge control panel - yet others do.

Hi! Thanks for your reply! Sorry to ask a silly question, but how do we tell it to run off 12v? Is that the battery option on the fridge? Also, on the main power unit, we just keep all the buttons on for power, including charger one. We also have tried running the car and revving the engine before trying again to set up the fridge but still to no avail..... thanks again! 😊

Yes, battery = 12v. Mains hook up = 240v. Engage battery function when connected to car with the engine running.

Do you know an experienced caravanner who can talk you through these things and show you how it all works?

There are two quite seperate 12v connections for a fridge.

One is part of the caravan electrics and comes from the leisure battery via a dedicated fuse - which is sometimes not in the main fuse panel but hidden away where it suited the manufacturer. This runs the controls, light, etc.

Other 12v supply should come direct from the tow vehicle and is completely seperate from the caravan electrics. It is fed from a relay in the tow vehicle which only supplies power when the engine is running. Recently car builders have tried to get clever about electrical load and even if the 12v caravan fridge wiring is present it may not come on when you expect.  A friend with a test meter or bulb can verify that at the 13-pin car socket while you run/rev the engine.

So in some caravans with some fridge models you need the caravan 12v electrics to be functioning correctly to operate the control panel so it will switch to 12v operation AND the 13-pin plug in a vehicle that is actually supplying the high current 12v to cool the fridge. 

It is done this way because the high current needed to cool the fridge will empty a leisure battery in no time at all.  And it all needs to be done with the blue 240v mains plug removed.

As TW says, a local caravanner should be able to show how it works, and you can look at his/her caravan as well. Or a caravan dealer, or shop, or site.

Do you have a handbook for the caravan? If not, they are downloadable from the Swift website. (Swift Ace Viceroy sounds like a Wandahome South Cave special edition based on a Sprite model)

Even if the car supply is OK, the 'black button' needs to be on, the battery symbol on the fridge selected, and even then, until the engine is started, the lights will flash, but after a few seconds, they should stop.

Hi everyone! Thanks to you all for your replies 😊. We've managed to locate the second fuse board (under the front settee area as mentioned) to check fuses, and all is OK there. When the car is hooked up, weve tried revving it a few times to boost connection, but the fridge still won't set, despite the black power button being on, and the vehicle battery displays nothing....the manual says both the leisure and vehicle battery indicators should flash together when the car has been connected, but don't think this is happening either.

The van is going in for a small repair in a few weeks, so I think we will ask the service people to try and investigate whilst it is connected to the car when we take in the van.  Hopefully, we can solve the mystery! Thanks again to everyone.

You don't say what vehicle you are using to tow.  We had an Octavia from new, factory fitted with towbar and electrics.  We had exactly the problem you describe, which was due to lack of suitable power supply being fitted by continental manufacturers for some reason.  We had a separate, additional power supply installed by a local towbar installer, and all was well after that.  I was told, but obviously don't know how true this is, that most continental caravans don't have fridges (!!??) and thus don't need this supply.

We have just changes cars, and made sure the new towbar installation allowed for electrical supply to the van.  It does, but this installation at least requires the engine to run to flow electric from the car to the van.  Presumably this is so it will not run down the car battery if hooked up overnight on say a long ferry crossing.  Seems strange to me that you have a wacking great domestic battery on the van, and it doesn't use this as the primary source - so the fridge runs overnight on this if required. 

Perhaps someone else can answer this particular query.  

The fridge element draws far too much power to run it for any length of time on the van leisure battery.

Are you sure that the car socket is actually wired for the fridge auxiliary supply? Sometimes cars are wired just for a trailer and not fully wired for a caravan which requires a relay to switch the auxiliary supply on when the engine is running. You would need a voltmeter to check the socket.