Electrics Confusion

Not sure what switches you have on your fridge, I have 240/battery/gas and I select 'battery' if I want the fridge to chill whilst towing. Providing that your car is wired correctly, your fridge will only work when the engine is running. Your Car/off/caravan switch is only for when you're connected to your tow car to give you the choice of where your 12 volts comes from to power your caravan short term in a lay-by etc. It's nothing to do with powering your fridge while on the move. Again, when on EHU it doesn't make any difference which position the switch is in. 

When on EHU if you want your battery to stay charged and therefore things like your toilet flush & 12 volt lighting to work, then leave your charger on.

Thanks that makes more sense to me now.  However, If the car/off/caravan switch is nothing to do with powering the fridge then how is the fridge powered when on a non EHU site?  Does it automatically detect that the car isn't connected and therefore default to the leisure battery when the fridge option is set to battery?

When on a site withuot EHU you only have the gas option available

Your fridge will only operate on the battery when the battery is being charged while the car is running. On site, with out EHU you will have to turn it onto the gas setting and probable have to manually ignite the burners.

Thank you.  I didn't realise that. 

We were advised that the best idea with the car/caravan/off selector switch was always to leave it in "caravan" position.

When you connect to your car and turn on the engine, there is a relay in your car that sends the 12v power to the fridge, and in your caravan there is one called a "habitation relay" that then turns off all the  12v power from the caravan battery to things such as the pump, the heater fan and the lights.

It should all work automatically, all you need to do is the selection of 12v on the fridge, unless you have one that self selects.

Which make and model of fridge do you have?  And do you have all the handbooks?

You can download the Swift handbooks from their website, look under "handbooks" and then "archive" and select your year.

A full fridge handbook should also be available on the manufacturer's website.

For questions regarding your van, I suggest you also join SwiftTalk, on the forum you will find lots of useful information, and can also ask questions directly of Swift.